Eileen here. We’ve all heard some of the general “rules of thumb” for stocking an aquarium: an inch of fish per gallon, one fish per gallon, more fish = less aggression and countless others. So, what works best? There are several approaches that can help make stocking an aquarium easier.

Research, research, research!!

It’s no secret that I for one am a big fan of research. I’m not talking in depth taxonomic studies or long term observational studies, just a little planning and reading up on what you would like to keep. We get a lot of questions like “I set up a tank, now what can I put in it?” or “I bought this pretty yellow fish, what can go with it?”. You may be able to save yourself some time, frustration and possibly disappointment by planning out what you might like in your tank before setting it up or buying any fish for it. It also helps you decide what you would like to put in it down the road. That way, you will be able to decorate and filter your tank in the best way for what you’d like to keep and you’ll avoid getting those impulse-buy tankmates that eliminate any chance of having that special fish you’ve had your eye on for months.

Along these same lines, be sure you are aware of the behavior of each item you choose and its requirements. There is nothing worse than bringing a fish home, only to learn that you have to spend more time preparing its food than your own, or finding out that it is a known predator of that favorite fish you already had. A few basic aquarium fish books can help a lot with the basics and can even help you find fish you never even knew existed. You could try shooting us a blog question, email (marinebio@thatpetplace.com) or giving the store a call at 717-299-5691 if you’re looking for help in this regard too.

An inch per gallon? Only sometimes

This is one of the most common stocking “rules” we hear but is often misunderstood and misused. Let’s compare a few common groups of freshwater fish: tetras, goldfish and cichlids. First, the “inch per gallon” or “fish per gallon” rules have to take the adult size of the fish into consideration. Sure a fish might be one inch when you buy it, but if that fish grows into a footlong adult? That changes things. Then, what about the body mass of the fish and the waste it produces? Six little one-inch-long tetras will certainly affect an aquarium different than a six-inch-long goldfish. Goldfish just produce a whole lot more waste, eat a lot more and have a lot more mass and size behind that six-inch-length than all of those little tetras put together. Next, what about the behavior? That same six-inch goldfish is going to have a far different temperament than, say, a six-inch Green Terror cichlid. Two six-inch goldfish could be perfectly happen in a well-filtered 45 gallon aquarium; the two Green Terrors may well try to kill each other. So do we throw out the “inch per gallon” rule altogether? Not necessarily. It is fine to use as a very general and basic guideline for small fish like tetras, danios or livebearers if you take their adult size into consideration, but don’t take it as gospel if you are keeping anything larger.

Zone Defense: It works in sports, it works in aquariums

When stocking your tank, keep in mind that all of the fish won’t be spending all of their time in the same area of the tank. Looking at your aquarium from the front, you can divide it horizontally into 4 zones. The middle two zones are where a lot of fish hang out. In freshwater, this is where you’d find tetras, angelfish, barbs, and some cichlids. In saltwater, this would be your tangs, damsels, clownfish, and some groups of wrasses. The top quarter section is more of the top dwelling fish. In freshwater, these are fish like hatchets, killifish, rasboras, and mollies and in saltwater, this would be some cardinals and dartfish gobies – fish whose mouths are more on the tops of their heads and point upward for those prey items on the surface. The last section, the one on the bottom of the tank, is home to the bottom feeders – catfish, blennies, loaches, and gobies. Some saltwater fish and freshwater cichlids that spend a great deal of their time in and around rockwork also would count towards this group.

Stocking an aquarium with all three sections – top, middle, and bottom – in mind will help you make the most of the space you have. Instead of having a lot of fish that hang out in one of these zones, choosing fish from all three can give you a more complete look to your tank and can help spread out the activity and aggression throughout the whole tank.

The more, the merrier? Or one big spotlight?

There are two big ways to plan an aquarium – having an active tank with lots of activity and schools of little fish, or have a showcase item like a big saltwater angelfish or showing cichlid and build the rest of the tank around it. Both can be stunning in their own way but take some planning. Having a tank full of different schools of little fish can be interesting and active. You can have a higher number of fish this way but there isn’t one big thing to focus on. Or, you can have one big fish like a Discus and complement it with just a few other little fish for some subtle activity and to help with clean-up. Some of the most interesting tanks can be species-only tanks. These tanks have just one kind of fish like an aggressive cichlid or a saltwater oddity like a frogfish, and nothing else. These are the true “pet fish”. They can be fascinating but aren’t as diverse as community aquariums.

Biotopes – a little piece of nature.

Some of my favorite aquarium have been biotopes. These are tiny pieces of a specific environment where everything in the aquarium is designed and chosen around that location or habitat. For examples, a Caribbean biotopes would have only fish and invertebrates chosen from the Caribbean, so a fish from the Indo-Pacific would not be chosen for this tank. This is how most public aquariums are designed and is one of the more collector’s approaches to aquariums. Instead of relying on the impulse buy, this method is all about planning and choosing the perfect addition for your little slice of nature. Much better than a postcard for remembering that trip to Hawaii!

These are just a few approaches to choosing the next addition to your favorite aquarium. Feel free to share your own and never be afraid to ask if you aren’t sure if what you want is right for you!

Eileen here. Some myths and legends are universal. Almost every country has some version of a “bigfoot” legend. Nessie is one of Scotland’s biggest celebrities. People are abducted by aliens and UFO’s are spotted in the sky around the world. What does the aquarium hobby contribute to this list?

 

“Fish only grow to the size of their aquarium.”

Like most of those other stories, this one likely started because people saw some truth behind it. They saw their fish grow large in relation to their aquarium, stop growing, then die. But, just like we now know that the Earth is not flat and we will not fall off the edge of it if we sail too far, we now know that the size of an aquarium does not dictate the size of a healthy adult fish.

The most common victim of this theory is the  comet goldfish, the fish often sold as very inexpensive feeder fish or won in carnival ping-pong ball toss games. People win the fish or buy them as inexpensive pets, not knowing that the tiny fish they took home should be able to become an 8-10 inch adult with a lifespan of 10 years or more if well cared for. “Goldfish bowls” are sold almost everywhere that carries fish supplies. Small aquariums – 10 gallons or under – are often sold with pictures of small fancy goldfish on the box so it is no wonder that people may be unaware of the problems they are walking into.

Keeping any animal, fish or otherwise, in a habitat that is too small for it causes a number of problems that might not be obvious at first. The fish people win at carnivals or purchase as small juveniles might be fine for a short time in a small aquarium, but as the fish grows, so does its requirements. Looking at the same situation in terms of a person instead of a fish, it becomes more obvious. An infant, for example, doesn’t require much space for his needs to be met. He can feed and exercise within the area of his nursery and regular cleanings can keep his nursery healthy. But, as the infant grows into a toddler, his needs also grow. He requires more space to exercise so his muscles develop properly. He is growing and needs more food and so produces more waste as a result that the same regular cleanings the infant received cannot control. As he grows through his life, that boy can certainly grow into a man if never let out of the nursery that he was kept in as an infant, but that man will not be as healthy as he could be. His hygiene and development will have suffered from being kept in a confined space and not allowed to flourish and develop properly and he will probably not live as long as a man whose environment has been allowed to grow with him.

The same happens when a fish is kept in a small tank. As the body of the fish grows, so does the amount of waste it produces and the food it needs. This can affect the water quality of the aquarium and lead to disease caused by high ammonia levels, high nitrite levels, low dissolved oxygen content, low pH and other incorrect parameters. Just as a person kept in a small space cannot grow properly, the fish would also physically not be able to grow to its full size. Its body and skeletal structure may be stunted by the lack of space and ability to exercise and swim as it should, but the internal organs often continue to grow at a normal rate. The internal damage this causes, in combination with water quality issues, will lead to a premature death.

While a small tank can certainly affect the size of the fish, it is not the way that we once believed. There is no internal sensor in a fish that can detect the size of its environment and adjust its growth accordingly. The fish we keep are  just as dependent upon us as small children to give them the proper care needed to keep them healthy so it is up to us to be aware of what their needs are and to do our best to make sure those needs are met throughout the fish’s life.

Especially for beginners, getting what you need for setting up a saltwater or reef aquarium can be daunting.  One of the most confusing aspects of the process may be Live Rock.  Here are some common Q & A that may make it a little clearer for anyone, especially those who just starting out.

Do I need Live Rock and what is its purpose?

Live rock is the calcium carbonate skeletons of ancient corals and other calcareous organisms, which forms the base of coral reefs.  It is not actually “alive” but is it is usually encrusted with coralline algae and inhabited by microscopic and macroscopic marine organisms.  The organisms on the live rock help to establish the biological base of the aquarium.  The rock serves as a biological filter hosting nitrifying bacteria that fuel processes like the nitrogen cycle to eliminate organic waste.  Live rock also has a stabilizing effect on the water chemistry, especially helping to maintain constant pH by releasing calcium.  The other obvious purpose is for decoration.  The rock, once established, serves as a shelter for fish and inverts, as a decorative element encrusted with colorful coralline algaes and other organisms (that may appear to spring from its surface from nothing), and as a platform for corals that you introduce to grow onto.

What is the difference between natural and cultured rock?

There are many varieties of live rock.  Most are named for the region where they are harvested, and often they have distinctive forms and characteristics. Some are dense, some are lighter and more porous, some are branchy, some are plate-like, ect.  They all basically serve the same purpose, and they may be mixed and matched according to your taste and needs.  Natural rock is chipped off and collected from specified areas in designated regions.  This rock is naturally occurring and highly variable.  Cultured rock is man-made from specially mixed concrete that is formed into basic shapes and then placed in the oceans near reefs for a period of 1-5 years where it is seeded with the same micro and macro organisms as natural rock. The rock is then collected and distributed for aquariums.  Cultured rock is favorable as it has the same benefits to the aquarium, but less environmental impact and is sustainable. It is typically less variable in shape.

How much rock do I need?

You may hear different opinions on how much rock you need, but it will depend on what your intentions are. Generally, the rule of thumb is 1-2 lbs per gallon.  This amount can vary depending on the arrangement you want and the density of the rock.  You may choose to purchase all the rock you need when setting up the tank initially, as the rock be used to cycle the tank, and will cure in the process.  Otherwise you can buy the rock a few pieces at a time, cure it in a separate vessel then add pieces periodically until the arrangement is where you like it.  The other option is to purchase base rock and cover it with fresh live rock.  Over time the base rock will be seeded by the live rock.  Just be sure your arrangement has spaces where the water can circulate through the rock and dead zones don’t occur.

What is curing and how do I cure rock?

Curing Live Rock means conditioning or cycling it for use in your aquarium. Cured rock has already been conditioned and is stable to use right away in an aquarium with minimal concern of fluctuations in water chemistry.  Fresh live rock is not cured and it shouldn’t be placed directly into a main aquarium until you cure it.  The collection and shipping process of most rock involves it being out of the water for days at a time, and a lot of the organic matter on the rock dies off.  By tanking and curing the rock, you allow the rock to recover from these stresses.  The dead matter breaks down and new beneficial organisms have the chance to re-establish and freshen up.  If you purchase fresh rock, a saltwater rinse or dip and shake will help to remove loose debris and some of the dead matter to kick start the curing process.  You can learn how to cure live rock in this short video.

How long will it take for stuff to start growing on my rock?

Once the rock is in the tank and the rest of your set-up is complete with adequate lighting, skimmer, and circulation, additives such as calcium, iodine and strontium will encourage the growth of colorful coralline algaes, and contribute to the health of other forms of live rock growth.  As the tank establishes and becomes more stable, you’ll probably see a variety of organisms from macroalgaes to small corals and other sessile inverts.  Each tank and each piece of rock may reveal different surprises, but the important thing is patience.  Taking the time for careful set-up and maintenance and a time allowance for the tank to progress at a comfortable pace will result in a healthy and sustainable reef environment.

Hello, Frank Indiviglio here. Please see Part I of this article for information on using plants and bacteria to control algae. Today I’d like to take a look at some algae-eating fishes, snails and shrimps.

Sucker Catfishes (Plecostomus, Hypostomus, Loricarichthys spp.)
An incredible array of fishes consume algae, with these interesting beauties being among the best known. Larger sucker cats and Chinese sailfin sharks (see article below) can also be kept in outdoor ponds.

Thailand Flying Fox, Epalzeorhynchus kallopterus
This nicely marked fish consumes all types of algae, and is also fond of the flatworms that sometimes arrive in aquariums along with live plants.

Siamese Algae Eater, Crossocheilus siamensis
This fish is similar in appearance to other, less-effective species, and is sometimes sold as the “True Siamese Algae Eater”. It does well in schools, and consumes even the coarser varieties of hair and beard algae.

Chinese Hillstream Loach, Beaufortia kweichowensis
This small loach is one of my favorites. It has been compared to a flounder in appearance, but reminds me of the oddly-shaped torpedo rays.

This active loach is adapted to fast-flowing waters, and fares best in high oxygen environments. It is well-suited for removing algae from glass and plant leaves, and is rarely if ever bred in captivity…definitely a fish worth working with for those interested in breaking new ground.

Garra pingi pingi or Pingi Log Sucker, Discognathus pingi
Formerly rare in the trade, this stout East Asian bottom dweller has a huge appetite for algae of all types. Many aquarists find they must supplement its diet with algae wafers; those I have kept took pre-soaked kale as well.

This is another species which would make a nice breeding project, as only wild-caught animals are available at this point.

Algae Eater, Gyrinocheilus aymonieri
The “standard” algae control fish in smaller aquariums, the taxonomy of this interesting species is somewhat of a mystery. While typically reaching 4 inches in length, I recall receiving shipments of individuals that topped 11 inches. I hope to keep some in an outdoor pond in the future, to see if the increased water volume might spur additional growth.

Algae eaters relentlessly comb rocks, glass and plant leaves for algae, and will take leftover fish flakes as well.

Freshwater Shrimp
Almost all of the dozen or so species currently available favor algae as food. Particularly attractive is the cherry shrimp, Neocaridina denticulata sinensis. Given proper care (please see article below) they will breed prolifically, with a large group making for a spectacular display.

Freshwater shrimp will co-exist with the fish mentioned above, but will, however, be harassed or eaten by fishes with carnivorous tendencies.

Snails
A number of snails live almost entirely upon algae, but many consume plants as well. Apple snails can eat a surprising number of plants overnight, while olive Nerites (please see article below) take only algae and do not reproduce in fresh water. The Japanese trapdoor snail is also a good choice, but needs warm, well-filtered water.

Further Reading
To learn more about some of the creatures mentioned above, please see the following articles:
Freshwater Shrimp

The Chinese Sailfin Shark

The Olive Nerite

Please write in with your questions and comments. Thanks, until next time, Frank Indiviglio.

There are four main categories that fish diseases can be divided into: Bacterial, Fungal, Parasitic, and Environmental. Some conditions can be caused by more than one of these (like secondary fungal infections at the site of a bacterial infection, or bacterial infections caused by poor water conditions) and identifying the cause of the issue is often important to helping to resolve it. 

---

Some general information on these types of conditions:

Bacterial Infections:  Bacterial infections are some of the most common and widespread conditions in aquariums. They may looks like a rough white coating, red patches or red sores, frayed or deteriorating fins, cloudy eyes or other similar visible symptoms depending on the exact bacteria. The edges of sores may be white and fuzzy, especially in the case of a secondary fungal infection also affecting the site. General bacterial infections are usually caused by a wound or injury, or poor water conditions like high Ammonia or low pH. They may be worse in fish already stressed by transport, bullying by tankmates or poor or improper water parameters. It is important to get rid of any causes of the infection or any conditions that may be making it worse. ALWAYS test the water quality to make sure the pH and temperature are appropriate and the Ammonia and Nitrite levels are zero or very minimal; fix any levels that are off before attempting to treat or medicate. If the water quality is good, a medication can be used if necessary. Some infections will clear up on their own once the conditions are improved but some mild medications or dietary supplements can help the healing. In severe cases or with some tankmates, a stronger medication might be needed and should be done in a separate quarantine system.

Fungal Infections:  Fungal infections usually look like a cottony patch on a fish, particularly around the edges of a wound. Waste like leftover food can also grow a fungus, as can ornaments that are improperly cleaned. Using some air fresheners, cleaners or oils in the vicinity of the tank can also cause a white coating to grow on surfaces. It looks like tufts of cotton and can appear anywhere on the fish, particularly around an existing wound. Fungal infections are usually a secondary condition that appears because the fish is already weakened by another problem. Slow-moving fish like Bettas are vulnerable to a body fungus if the water is too cold for the fish to remain active or if the fish’s metabolism is slowed. Wounds may have a secondary fungal infection around the edges, especially if the water is dirty. Waste or decorations may grow a fungal coating if the water flow is too low to move the waste so it can be removed by the filtration. Improve the water flow, temperature, water conditions or other parameters that may be allowing the fungus to grow. Medication can be used in some cases but most mild fungal infections will clear up on their own once the cause is addressed. 

Parasites: Parasites in general are one of the most common aquarium maladies next to unsuitable water conditions. Parasites by definition are any organism that requires a host organism to live, often to the detriment of that host and may lead to the death of the host. The size of parasites varies greatly from tiny organisms like those responsible for Ich and Marine Velvet, to larger crustaceans and worms like flukes, anchor worms or fish lice. These parasites can also be external (living on the outside of the body of the fish) or internal (living inside the fish, often in organs like the digestive system). Common signs of parasites are rapid breathing, weight loss, white feces, sores or a flicking or scratching behavior against rocks and surfaces. Different parasites require different treatments and treatment methods and so should be carefully diagnosed before medicating or treatments.

Environmental Stress/Biological Conditions: Environmental stress can result from improper water conditions (temperature, pH, salinity, etc.), unsuitable decor (too much or too little vegetation or decorations, too intense or dim lighting, etc.) or exterior conditions like activity in the room around the tank or vibrations caused by an unstable surface or tapping on the tank. Some biological conditions like poor nutrition, improper diet or poor breeding can cause problems as well. Some of these stresses can be easily fixed while others can be more difficult. Poor health or unusual behavior (including jumping from or trying to jump from the tank) can hint towards something wrong with the fish’s environment. Researching all choices for an aquarium and observing behavior regularly can help an aquarist to notice these problems.

---

Some more specific diseases and conditions that aquarists commonly encounter: 

(  B  : Bacterial,  F  : Fungal,  P  : Parasitic, E : Environmental/Biological) 

Ammonia Burn ( E ) : As the name suggests, this is a burn-like injury caused by highly acidic ammonia build-up. Ammonia can cause open wounds on a fish’s body or damage to sensitive structures like their gills. These excessive ammonia levels are commonly caused by poor filtration or overstocking with too many fish or fish too large for the tank. Treatment includes eliminating the cause of the high ammonia level, neutralizing or removing the ammonia, and treating the wounds if necessary to avoid infection. 

Aeromonas ( B ): Aeromonas infections are caused by several species of bacteria that are opportunistic and will affect organisms with weakened immune systems. It can affect fish, amphibians and even humans in some cases. Koi and other pond fish are vulnerable to Aeromonas infections during the early spring and summer when temperature fluctuations can leave them vulnerable and weakened. Aeromonas attack organs and will digest gelatin and hemoglobin cells. It often appears as deep open sores on the body of a fish as well as causing severe weight loss as it attacks the internal organs. Aeromonas bacteria is very resistant to most medications and can be very difficult to treat. Strong gram-negative bacterial medications both in the water and in food treatments can be used. Injections are also sometimes used by veterinarians and biologists to treat larger fish.

“Black Ich” or “Black Spot” ( P ): This disease is a parasite infection caused by flatworms. It mainly affects tangs and surgeonfish and appears as small dark spots on the body of the tang. The fish may also flick or scratch against surfaces or may be less active than normal. The flatworm lays eggs on the body of the fish and drops off within a few days, leaving the eggs to hatch on the fish a few days after that. Treatment for Black Ich can include freshwater baths or antiparasitic medications with active ingredients like formalin.

Brooklynella ( P ): This parasitic infection is also known as “Anemonefish Disease” or “Clownfish Disease” due to its most common victim. It is a protozoan that usually spreads very quickly and is almost always fatal and has no commercially-effective treatments. It can first be seen as a fine sheen on the affected fish – usually newly captured or transported fish – but soon evolves to signs of physical stress to the fish, difficulty breathing, and excessive slime coat production. As this slime coat sloughs off the fish, it can spread the protozoans throughout a system to prompt quarantine of an infected fish is absolutely important. All tank equipment should be cleaned and sterilized well as well to avoid spreading the disease. As I mentioned, there are no medications that are known to be very effective on these protozoans, but medications like those containing formalehyde, malachite green and and methylene blue used in a quarantine tank can help. Do not use freshwater dips with this infection.

Columnaris/”Mouth & Tail Rot” ( B, F ): With this bacterial infection, the “tips” of the fish – lips, mouth, and tail – are affected first. They develop a milky-white coating and appear to “rot away”. It may be accompanied by a cottony-looking secondary fungal infection. In some fish – Rainbowfish especially – the gram-negative Columnaris bacteria responsible for this condition cause saddle-like patches starting at the back and dorsal fin and extending down the sides of the fish. Both of these forms may appear at the same time or you may only see one at a time. Poor water quality or sudden changes to their environment can leave fish vulnerable to this bacteria. It is important to improve any of these negative conditions before treating, and if medicating, be sure to use a medication for gram-negative bacteria. 

Dropsy ( B, E ): This is an internal condition that causes multi-organ failure, and is very difficult to treat. It is usually caused by an internal bacterial infection that causes the fish to retain fluids internally but can be brought on by other conditions or environmental stress. The fish often look like “pine-cones”, with their scales sticking out, off of their body. They are often listless, won’t eat, and sit at the bottom or in one area of the aquarium. Remove this fish as soon as you can and treat it in a quarantine tank! If the fish is eating, treat its food with an antibiotic. If not, treat the tank water with a strong antibiotic and hope for the best. If dropsy isn’t caught in its early stages (lethargy, swollen abdomen, swimming in a bizarre manner) it is almost always fatal.

“Fin Rot” ( B, F, E ): Fin rot can be more of a symptom than a disease in some cases (outside of the Columnaris/ “Mouth & Tail Rot” described above) and is essentially just what the name describes. The fins on the fish, most often first noticed in the caudal (tail) fin, will appear to be rotting away and may be red and ragged. The fins may also appear white as a secondary fungal infection sets in in some cases. This is usually caused by a bacterial infection and can be the result of bullying or fin-nipping tankmates or poor water conditions. The cause of the condition should be address (water quality improved or aggressive tankmate removed) and the fish can be treated with an antibiotic or antibacterial medication.

Head and Lateral Line Erosion (HLLE) ( E, P ): Head and Lateral Line Erosion (HLLE) is seen mostly in saltwater tangs and angelfish but other fish are also susceptible. Another similar condition, known as Hole-in-the-head, is very similar in appearance but mainly affects large cichlids and freshwater fish. With HLLE, the area around the head and eyes and the length of the lateral line down each side of the fish’s body becomes pitted and can appear to be rotting away. While not usually fatal in itself, HLLE can cause permanent scarring and is a symptom of a more serious and ongoing condition like poor nutrition. Fish like tangs that are especially vulnerable to this condition should be fed a varied diet high in fresh macroalgae. Vitamin supplements can also be helpful. Some research suggests that HLLE can also be caused at least in part by other stresses like some flagellate parasites or stray electrical current.

Hole-in-the-head Disease ( E, P ): Hole-in-the-head is very similar to HLLE, described above. Some aquarists argue that these two names refer to the freshwater and saltwater versions of the same condition since they share some of the same causes and symptoms. Hole-in-the-head is found mostly with large cichlids like Oscars and Discus but can affect other fish as well. Like HLLE, the main cause is usually linked to improper diet or water conditions and adding vitamin supplements and a varied diet can often help stop and reverse some of the effects of the disease. Hole-in-the-head is also attributed more to parasite infections than HLLE, specifically protozoans.

“Ich” ( P ): Ichthyophthirius multifiliis, also known as Ich, Ick, or White Spot, is one of the most common and well-known conditions in the aquarium hobby. Many aquarists incorrectly diagnose problems with their aquarium as ich when it is actually another condition. Ich is a parasite that affects freshwater fish (as opposed to the similar Cryptocaryon that affects saltwater fish but has an almost identical appearance, symptoms and treatment). Ich appears as small white spots on the body of the fish. These spots look like grains of salt as opposed to the cottony tufts of fungal infections, the dust-like appearance of oodinium or some bacterial infections or the pits associated with Hole-in-the-head and HLLE. The fish may stop eating, may scratch and rub against surfaces, and may appear lethargic. Treatments include increasing temperature, adding vitamin and garlic supplements, freshwater or saltwater “dips”, and a score of medications. The parasite also has a life cycle that allows it to remain dormant in an aquarium or on a fish for weeks at a time before blooming when triggered by environmental conditions or the fish’s immune system being weakened by stress or anther condition. Some medications available to treat ich are not safe for all fish or for invertebrates; be sure to choose the medication suitable for your aquarium. 

Internal Parasites ( P ): Internal parasites can be diagnosed externally by white, stringy feces and a sunken stomach or eyes as the parasite steals the nutrients from the fish. Internal parasite – most commonly types of worms – can affect the fish most commonly from infected live or fresh foods. External medications that are added to the water are less effective on internal parasites. It is best to treat the fish’s food by soaking the food in a medicated solution before feeding. Garlic supplements and other vitamins also may help expel the parasite and help the fish replenish its nutrients and fight off the parasite on its own. 

“Lymph” (Virus): Lymphocystis, commonly known as “lymph”, is a virus that affects both freshwater and saltwater fish. This virus forms white cauliflower-like growths on the fins and body of the fish and can cause white patches around the eyes. It usually develops when the immune system of the fish is weakened due to poor nutrition or water quality. Being a virus, there is no reliable medication to treat it but improving the conditions and diet will help to boost the fish’s natural immune system and can help the fish fight it on their own. Some sources recommend removing the nodules by scraping them from the body or fins; this can be a dangerous approach that may lead to excessive stress and secondary infections. Lymph is not usually fatal and often may clear up on its own as the fish fights off the virus.

Marine Velvet/ Oodinium ( P ): Marine Velvet, also known as Oodinium, is caused by the parasite Amyloodinium ocellatum. This is one of the most fatal parasitic infections as it is very contagious and resistant to most medications. Marine Velvet looks like a very fine velvety coating on the fish as opposed to the salt-like spotting of Ich. The fish may also breathe rapidly and have cloudy eyes. Quarantine and treat any affected fish as soon as possible with a strong antiparasitic treatment like copper sulfates. The salinity can also be lowered and a UV sterilizer can be used to help kill the parasites.

“Neon Tetra Diseases” (NTD) ( P ):  Despite the common name, this condition affects many more species than just Neon Tetras; most freshwater fish like tetras, danios, rasboras, rainbowfish and more can be affected. It typically first appears like a saddle extending around the dorsal fin on the back of the fish similar to the Columnaris infection described above. Rather than the fuzzy, wispier look to Columnaris patches, NTD looks more like the color and scales have been “erased” from the area. The fish may swim erratically or its body may start to appear bend downward at the spine.  NTD is caused by a Microsporidian parasite. This is an internal parasite that starts affecting the fish from the inside rather than the external parasites like Ich more commonly encountered. This parasite can be highly contagious and is usually spread by eating infested foods or fishflesh. There is no effective treatment for this condition. Once a fish shows symptoms, it is best to move it into a separate quarantine system or euthanize it to avoid spreading the parasite to other fish. 

Pop-eye ( B, E ): Like the name suggests, “pop-eye” is a condition in which one or both eyes of the fish appear to be swollen and popping out of the socket. This can result from a bacterial infection, poor water quality, injury or in rare cases a gas pocket in the eye socket. This is typically a symptom of an underlying condition like poor water quality and is difficult to treat specifically. Anti-bacterial medications may help but the water quality and any other possible causes should be addresses as well. Pop-eye may often clear on its own but may lead to decreased vision in the affected eye.

Scar Tissue/Cysts ( E ):  Sometimes confused with Ich, these irregular lumps are usually only along the spines in the fins. They are caused by a blood vessel blockage or scar tissue due to broken spines, poor breeding, poor water quality, or stress. It can sometimes – but not usually – be an early sign of or lead to a secondary disease like Fin Rot. They are usually seen in fish with larger fins like Angelfish, Guppies, Bettas or selectively-bred longfin varieties of other fish. Usually benign and harmless, they are not usually treatable but usually disappear on their own.

Septicemia ( B, E ): Septicemia is an infection in the blood. The infection itself is bacterial but usually occurs when a fish is left vulnerable due to poor water conditions. It appears as red streaks in the fins and body and open sores or deteriorating fins in more severe cases. Any environmental conditions like poor water quality must be improved and resolved as quickly as possible. External bacterial medications in the water may help but pretreating the food with medication and using internal bacterial medications is more effective. Catching this infection as soon as possible drastically improves survival rates.

Swim Bladder Infection/Disorders ( E ): This condition is seen mostly in fancy goldfish, balloon mollies and other fish bred for a similar “chubby” body shape. The swim bladder in fish is used to help control buoyancy (the up and down motion) through gas exchange within the fish’s body. The fish is considered “neutrally buoyant” when it is able to hover in the water without floating up or sinking down. If the fish is unable to achieve buoyancy, it may float, sink or be unable to swim properly or remain upright in the water. This may be the result of an internal bacterial infection that can be treated with some medications. Some fish, especially fancy goldfish, may gulp air at the surface will feeding and have similar issues caused by air in their digestive systems. Feeding them fresh greens like peas or zucchini may help get rid of this bubble.