That Fish Blog – Aquarium Advice and Information

Like their fellow hitchhiker-turned-aquarium-stars, the Mantis Shrimp, Pistol Shrimp are coming into their own as popular aquarium additions. Unlike the Mantis Shrimp, most Pistol Shrimp can actually be kept with other tankmates.  They may even form bonds with some tankmates like Shrimpgobies that can be fascinating and entertaining to watch. Here are a few species of popular Pistol Shrimp for home aquariums.

Pistol shrimp get their name from the loud popping sound they can make by quickly opening or closing their specially adapted claws. This is used as a defense mechanism to frighten off would-be predators and, unlike the Mantis Shrimp they are sometimes confused with, they are harmless to most tankmates. They can be kept with most fish that will not prey on them but should not be kept with some other crustaceans, especially small shrimp or lobsters.

Tiger Pistol Shrimp (Alpheus bellulus)

Tiger Pistol Shrimp (Alpheus bellulus)

The Tiger Pistol Shrimp is one of the most common and most popular pistol shrimp. It’s one of the species we get in to our store most often. These shrimp aren’t as striped as one would expect from a “Tiger” Pistol Shrimp but has a mottled, vaguely striped coloration in shades of tan, cream and reddish brown. The legs are striped and its claws have dark bands like the rubber bands on the claws of a lobster at a seafood restaurant. These pistols are true commensal species and may bond with any shrimpgobies – genus Cryptocentrus, Amblyeleotris, Stonogobiops and others. This species can grow up to about three inches in length and is one of the larger pistols.

Randall’s Pistol Shrimp (Alpheus randalli)

Randall’s Pistol Shrimp (Alpheus randalli)

The Randall’s Pistol Shrimp is also known as the “Candy Cane” or “Red-banded Pistol Shrimp” and is one of the other species that we get in most often. While the Tiger Pistol Shrimp has a more mottled pattern, the Randall’s Pistol has more solid bright red and white stripes over a somewhat translucent body. The body and legs may be yellow – sometimes bright yellow – in some shrimp. This pistol shrimp only grows to about an inch and a half in length but, like the Tiger Pistol, isn’t too picky about which shrimpgoby it forms a pair with. It is better for smaller nano-reefs than the Tiger Pistol Shrimp.

Red Caribbean Pistol Shrimp (Alpheus sp.)

Red Caribbean Pistol Shrimp (Alpheus sp.)

These pistol shrimp aren’t usually identified down to the exact species since several different species are almost identical. All are red with white markings, some with purple accents or banded antennas. However, these shrimp don’t usually pair with shrimpgobies. Instead, they form a relationship with the Curlycue Anemone (Bartholomea annulata), a common Caribbean anemone with long spiraling tentacles.

Green Pistol Shrimp (Alpheus euphrosyne)

Green Pistol Shrimp (Alpheus euphrosyne)

The Green Pistol Shrimp is one of the more understated species. These shrimp have a brownish, olive green color more suited to the environment where they live. Rather than the rocky coral reefs of many others, the Green Pistol is found in muddy estuaries at the mouths of rivers, usually in full saltwater but some can tolerate the more brackish waters closer to the bays and mouths of the rivers. These shrimp are best kept in tanks with deeper, finer substrate closer to the muddy bottoms they have come from.

Pocillopora Pistol Shrimp (Alpheus lottini)

Pocillopora Pistol Shrimp (Alpheus lottini)

Pocillopora Pistol Shrimp are fascinating and rare pistols with a different modus operandi than other pistols. Like its common name suggests, these shrimp live within Pocillopora colonies. They will sometimes live alongside other coral-dwellers like Trapezia crabs where they may even work together to fend off attacks from coral-eating starfish like Cushion Stars or Crown Of Thorn Stars. They stay fairly small, usually well under two inches, and can vary in color. Most are yellow-orange with purple markings like speckles or a stripe down their back. Some of these may be regional variations, others may be subspecies.

Bullseye Pistol Shrimp (Alpheus soror)

Bullseye Pistol Shrimp (Alpheus soror)

The Bullseye Pistol Shrimp is one of the most stunning in appearance. The body is bright yellow-orange and the claws, legs and antennae are bright purple. Although they are also sometimes known as “Michael’s Pistol Shrimp”, the name Bullseye Pistol Shrimp comes from the white-ringed black spot on the middle of each side. This pistol shrimp is another that doesn’t usually form a bond with shrimpgobies. Some may share a burrow with some shrimpgobies, but they aren’t as reliant on the bond as other pistol shrimp and will often live on their own without a goby and may leave a pair at any time. This species also tends to be more active and will venture further from home and more into the open than others.

These species are just some of the more common to enter the aquarium hobby. Others are sometimes available as well and each have their own unique behaviors and appearances but all can make for fascinating additions to a saltwater aquarium!

Skyrocketing in popularity over the past few years, Mantis Shrimp have gone from nuisance invaders to a specialty aquarium niche all their own (and a new superstar among viral animal posts thanks to comedic websites like The Oatmeal and zefrank’s YouTube videos). By far, the most popular of these crustaceans is the Peacock Mantis Shrimp, Odontodactylus scyllarus, but there are many other species that are just as fascinating and deserving of attention. We’ve featured mantis shrimp in general in several previous blogs; in this entry, we’ll investigate some of those other mantis shrimp that you may not hear about or see as much in media.

Gonodactylus smithii
Image © 2005 Roy Caldwell

Smith’s Mantis Shrimp, Gonodactylus smithii
Its name may not be too familiar, but this mantis is one of the most photographed species due to its trademark meral spot. As you may remember your mantis shrimp anatomy from our other posts, the “meral spot” is a pair of false eyespots on the mantis’s raptoral appendages (the gonna-hurt-you limbs). If you held your arms in front of you, the meral spots would be on the inner sides of your elbows. The Smith’s Mantis Shrimp is well known for these spots because they are some of the most easily-identifiable: bright purple with a defined white outline. They give the Smith’s Mantis Shrimp its other common name, the Purple-spotted Mantis Shrimp. The body color of the Smith’s Mantis Shrimp is otherwise pretty similar to the Peacock Mantis, often bright blue-green and sometimes with red trim to each body segment. This species is a “smasher” and while it isn’t available as often as some other species, it is very sought-after by collectors when it is.

Chiragra Mantis Shrimp: male (top) and female (bottom)

Chiragra Mantis Shrimp, Gonodactylus chiragra
This is one of the most common mantis shrimp that we receive at our store and is one of the best suited for aquarium life. It is the largest of the Gonodactylus genus of “smashers” but still only reaches about four inches in length. Unlike many other species, it is pretty easy to tell the difference between males and females. Male Chiragra Mantis Shrimp are usually blue-green in color while females are a mottled tan and cream. Both genders have a white meral spot that is far less obvious than the Smith’s. The most distinctive feature of this species regardless of gender is the light-colored sprinkles on the front corners of the carapace in the same place as the Peacock Mantis’s distinctive leopard spots.

Ciliata Mantis Shrimp and its checkerboard eyes

Ciliata Mantis Shrimp, Pseudosquilla ciliata

This is one of my favorites. Not only is it a “spearer” when most of the more common species are “smashers” but they have one of the coolest defining traits…checkerboard eyes. All mantis shrimp have extremely complex eyes and three different “sections” can be seen on most of them. The Ciliata Mantis Shrimp also has vertical lines overlaying the horizontal segments so their eyes, if you can get close enough to see it, have a checkerboard-like plaid pattern on them. Most of the Ciliata Mantis Shrimp you’ll see in the aquarium trade are green or yellow but their color and even pattern can change every time they molt depending on their environment and the lighting.

Zebra Mantis Shrimp, Lysiosquilla maculate

Zebra Mantis Shrimp, Lysiosquillina maculata
It is easy to see where the Zebra Mantis Shrimp gets its name. It has alternating black and cream-colored stripes. It also has white speckled antennal scales and eyes. However, it is unique in that, like the Ciliata Mantis, the Zebra Mantis is a “spearer”. Rather than hiding in rockwork caves like most “smashers”, these mantis shrimp will build deep burrows in the sand or substrate, reinforced with mucus, where they wait to ambush their prey. This species also has the distinction of being the largest of all mantis shrimp. While most of the Zebra Mantis Shrimp that you’ll find available to aquarists aren’t much larger than any other species available yet, they can grow to over fifteen inches in length!

**A species to avoid: Gonodactylaceus ternatensis
Several mantis shrimp with bright orange meral spots are also sometimes available. Two of these, Gonodactylaceus glabrous and Gonodactylaceus graphurus are almost identical and can be hardy, fun mantis shrimp to keep. A third, Gonodactylaceus ternatensis, is a less suitable choice. When small, this mantis shrimp looks like a juvenile Peacock Mantis but is often found living within coral heads. To collect it, the heads are often broken and destroyed. With all of the other species available, please avoid G. ternatensis and stick with the species collected with safer, less destructive methods!

These are just a few of the more common mantis shrimp other than a Peacock Mantis Shrimp but there are many other species that become available from time to time. So, don’t limit yourself if you are brave enough to head down the road to try these cool creatures!

• Smith’s Mantis Shrimp image used with permission from Roy’s List of Stomatopods for the Aquarium, ©2005 Roy Caldwell

With the new school year getting underway, it’ll only be a matter of time before the first science fairs and lab experiments start up. We get lots of students visiting or contacting us in search of ideas and test subjects for project ranging from the simple to the complex so I thought I’d share some tips and some of our favorite ideas for easy (and affordable) aquatic science fair projects for students of all levels.

Before you begin…

Before you start any experiment or project involving live plants or animals, it is important to make sure you are prepared for the maintenance, care and cost of the experiment and livestock they are taking on. We’ve had many students that have a great idea for a project involving crabs, jellyfish, “Nemo” clownfish or other animals but don’t realize how much work and supplies are going to be needed to keep these animals healthy. They are also a commitment after the experiment is done; fish aren’t disposable and you have to be ready for them to go from Test Subject to Pet at the end of the project. Some experiments also require multiple subject that each need their own setup and supplies.

Time is another important factor to consider with these projects. Many experiments involving fish and plants are going to take some time before you will really start to see results like growth or changes to color or behavior. It can take at least a few weeks to reach any conclusions so if this is a last-minute project, you might be better off heading in another direction.

What do you want to know?

The hypothesis of an experiment is the question you are trying to answer or what you are trying to prove or study. Depending on your grade level, this might be observing an environment or behavior or it might be testing a number of variables against a control. If one of the ideas here intrigues you but you aren’t sure where to go with it, ask your teacher or let us know and we might be able to help point you in a direction.

The project ideas here are mainly freshwater. Saltwater science fair projects are definitely possible, but they are going to be more difficult and expensive. Saltwater aquariums have a lot more factors than freshwater and need more equipment and maintenance to keep them healthy. If you already have a saltwater aquarium, you may be able to adapt one of these ideas to it or come up with your own but it may be easier to stick with a freshwater experiment if you don’t already have some saltwater experience.

Some Aquatic Science Project Ideas

A male Veiltail Betta

The Betta (“Siamese Fighting Fish”) as a test subject

• Betta splendens, also known as the Siamese Fighting Fish, is a good fish to use in aquatic studies and projects. They don’t need a lot of equipment or space, are easy to care for and are fairly inexpensive. They can be found in a lot of different colors and varieties but the most common kind that you will find in most stores is the Veiltail Betta. Some project ideas would be keeping bettas in a few different environments like a brightly lit versus darkened room, under a colored light like blue (“actinic”) light versus a white light, or warmer versus cooler temperatures. How do those changes affect each fish’s growth or coloration? You can take a picture every few days to compare any changes in their color or fins. Does the type of food or the color of the ornaments and backgrounds compared to the fish’s own color make any difference? Try different types or brands of food (flakes, pellets, frozen food, live food, freeze-dried food) to see how each affects the fish’s health.
• A good way to measure growth is to weigh a specific amount of water in a container without the fish, then weigh the same container with the fish. The difference between the two weights will tell you about how much the fish itself weighs and changes in that weight will tell you if the fish has gained or lost weight.

Fish Food Nutritional Comparison

Color-enhancing flake food like this is a common aquarium food.

• Anyone who has gone shopping for food for their aquarium knows how many choices there are for your fish. Flakes, pellets, frozen, freeze-dried, live, color-enhancing, vitamin-enhanced…the choices can be overwhelming. At the time that I write this, we have over 400 different fish food items on our website alone! For a science fair project, you can compare several of these foods and see how your fish react; feed the same kind of fish in separate but identical environments the same amount of different types or brands of food at the same time of day and measure how this impacts their growth, health and behavior. Maybe one kind of food is advertised as color-enhancing or another has a different primary ingredient…does one kind give the fish brighter colors or make them grow more during the time frame of the experiment? The fish should all be in separate aquariums to make sure they are only eating “their” food but you can otherwise use any fish – goldfish, bettas, livebearers like mollies or guppies. You can use the same method as above to record their growth.

The Nitrogen Cycle

The Nitrogen Cycle and “Cycling” a New Aquarium

• The Nitrogen Cycle is a process that every aquarium and contained body of water will go through as the helpful bacteria populations that take care of fish waste will go through. Every aquarist has seen this happen whether they realize it or not. As the first living critters in a tank produce waste or leftover food or other material decomposes in the tank, a bacteria known as Nitrosomonas change that waste from ammonia (NH₃) to nitrite (NO₂^–). Another population known as Nitrobacter will change that Nitrite into Nitrate (NO₃^–), the end product of the cycle which is usually removed by water changes or plants that use it to grow like fertilizer. If the levels of Ammonia, Nitrite and Nitrate could be put on a graph throughout the process, they should look like three hills with their peaks coming one after another. Can you set up and “cycle” a new aquarium and use test kits to record these values at a specific interval (every 5 hours, for example) and see if you can recreate this cycle? Does the number of fish change the levels or speed throughout this cycle? What about if the tank is cycled with a dead “waste” like leftover food instead of live fish?
• A project like this does use chemical test kits. The kits available from pet stores for aquariums are easy to use, but adult supervision should always be used around chemicals like these.

Fish Tricks

• Did you know fish can learn? Fish like goldfish have been “trained” to recognize objects and do all sorts of tricks like swimming through hoops or under limbo bars. There have even been “soccer matches” between saltwater fish to celebrate the World Cup. Training fish, like most animals, is all about positive reinforcement. Some companies have even made training kits just for teaching fish. Some experiments have trained fish to recognize certain colors by putting food in cups of one color (like red) but not others (like blue and yellow). Once the fish begins to associate the red cup with food, does putting a red ornament in the tank or red background on part of the tank make them choose that over the blue or yellow? How long does it take, and does any kind of fish learn faster than others? You can try putting one fish through its paces or train a few fish to compare their learning styles.
• Check out this video from Rochester Institute of Technology’s Professor Caroline DeLong to see how she taught a goldfish to recognize shapes

Brine Shrimp Hatchery Kit

Hatching Brine Shrimp

• Brine Shrimp are popular as fish food in aquariums as well as in the wild, and there was a time that “Sea Monkeys” were popular as “pets”. Hatching brine shrimp can be an interesting endeavor. They can be easy to grow but need just the right salinity (salt level) and the newly-hatched shrimp will need equally tiny food. The baby brine shrimp also show a behavior known as “phototaxis”, meaning they are attracted to light. Brine shrimp eggs are inexpensive and can be purchased in their dry “cyst” form where they will hatch once back in the right water. Experiment with salt levels, food like phytoplankton and with light and see what factors make for the best hatches. Once the shrimp are hatched, they can grow to almost a half inch in length and make great fish food!

This is just a sampling of some concepts that aquarists face every day and there are a lot more out there like overfeeding, breeding and genetics in fish like guppies or mollies, water changes and water chemistry…the possibilities are endless! Popular aquarium fish are even ending up in important medical research. Have we given you any ideas for your next science fair project or laboratory experiment? What would you like to learn more about, and what are some of your favorite projects? Share your results and experiences with us…we’d love to see the results of your studies!

Hiring staff for any job can be tricky. You need to make sure you have the right number of qualified employees to handle the job, not just a lot of employees on your payroll that eat into your bottom line or ignore the job you’ve given them. Choosing a clean-up crew for your saltwater aquarium is similar; you need to make sure you have the right snails and crabs and other cleaners for the tank without too many that can deplete your resources or just not even do the “right” work at all. “How many snails do I need?” is only part of the question; making sure you are getting the ones best suited to the job is just as important.

The White-speckled Hermit Crab. Cute, but NOT an algae eater!

Job Description and Qualifications

Hiring an employee without knowing their qualifications or describing the job doesn’t make much sense, whether it is renovations on your home or clean-up within your aquarium. Not all snails eat algae. Not all snails that eat algae eat the same kind of algae. Not all “algae” is even algae at all. And snails may not even be the best (or only) cleaners for the job; “detritivores” that eat the leftover food and waste (“detritus”) are also necessary for keeping a tank clean and healthy. The first step to choosing a clean-up crew is to identify what the problem is that you’d like them to help you solve. Algae is normal in any aquarium and having a basic clean-up and scavenger crew is a good idea but beyond that, if you have a specific problem like a cyanobacteria bloom, hair algae, green water or other issues, you may need a solution beyond a few snails. You may be seeing a symptom of a larger problem like poor water flow or lighting quality and unless that problem is addressed, it will keep coming back no matter how many snails or other clean-up crews you throw at it.

What are the working conditions?

It takes a different kind of person to paint the walls of a house than it does to paint the cables at the top of the Golden Gate Bridge. It also takes a different kind of critter to clean up a nano-reef than it does a rock-filled bare-bottom aquarium or a deep sand bed. Some hermit crabs can have difficulty reaching into small crevices and some snails can’t flip themselves over if they tumble off of the glass or rockwork. Some snails, starfish and other animals popular in aquariums also eat other snails or invertebrates and corals. Are the animals you are choosing suitable for the environment you have?

It’s all in the job security

Some of the most popular saltwater clean-up crew snails

Contrary to popular belief, snails and hermit crabs are not disposable or short-lived or robotic lawnmowers that feed on nothing but salt and sunlight. If they have plenty of food and proper care, they can live for a long time. If they run out of the right food, they won’t survive so overloading a tank with cleaners to keep it spotless is only going to end up with losses. When snails and other cleaners die and decompose, they affect water quality. When water quality goes down, algae will bloom. When algae blooms, you’ll need to add more cleaners. Starting to see where this cycle goes wrong? Avoid the urge to overload on a massive cleanup crew and start with a basic foundation. Once you can observe where they need the help, supplement with some helpers for that purpose (like aerating the substrate, cleaning the glass, targeting hair algae or other trouble areas).

The magic number is…

Just like the old “inch-per-gallon” rule that is still floating around for fish, there are some stocking guidelines for clean-up crews. Some of the most common include a snail per gallon or a hermit crab per five gallons but again, this only works if that snail or hermit crab is suitable. To help you out in making some selections, we have basic Algae Packs with recommended tank sizes. You can start with the one closest to your tank size and give it some time. You can always supplement later or get a specialty algae pack to target a specific need like detritus or hair and buble algae. Remember, hiring is always an ongoing process!

You’re hired!

Finding the perfect new addition to an aquarium is often like finding the Holy Grail to many aquarists. We all want the perfect little helper to keep the tank clean so there’s less work for us to do (and so our tank is cleaner and healthier, of course) but many “algae eaters” get too large for smaller aquariums and many others like the group of fish known as “plecos” don’t even eat algae at all. So what are the best plecos and algae eaters for small freshwater aquariums? Here are a few of our favorites that are some of the best choices for smaller community aquariums:

Bushynose & Bristlenose Plecos (genus Ancistrus)

Starlight Bristlenose Pleco (Ancistrus dolichopterus L183)

• PROS: Lots of variety in color and pattern, small size, vegetation-heavy diet (including algae), community-friendly.
• CONS: Some species grow larger than others, needs meaty foods as well, underfed fish may eat live plants.
• BEST SUITED AS: A community algae-eater and bottom-feeder.

Plecos from the genus Ancistrus usually have “Bristlenose” or “Bushynose” somewhere in their common names, a nickname that comes from the whisker-like frills that develop on most adults. They are usually more prominent in adult males but some females may get them too in some species. Different species in this group have different requirements, but they are generally among the smallest plecos. While they eat some meatier foods as well, most appear to eat mostly vegetation.

Clown Pleco (Panaque maccus L104)

Clown Pleco (Panaque maccus L104)

• PROS: Small size, easy-going temperament, fairly wide-spread diet.
• CONS: Need driftwood for grazing, not primarily an algae-eater.
• BEST SUITED AS: A general clean-up bottom-feeder for community aquariums.

The Clown Pleco is a popular small pleco. As with other Panaque plecos, these fish are omnivores and feed about equally on plants matter and meatier foods. Panaque plecos are also unique in that they actually feed on driftwood as well; make sure you have driftwood décor in your tank for these fish to graze on.

Hillstream Loaches

Reticulated Hillstream Sucker (Sewellia lineolata)

• PROS: Eats algae, can be kept in groups, unique and unusual appearance.
• CONS: Needs high flow and pristine water, vulnerable to aggressive tankmates and poor water chemistry.
• BEST SUITED AS: A unique addition to a suitable community aquarium where it incidentally may help eat algae but isn’t the primary algae-eater.

Hillstream Loaches have flattened guitar-shaped bodies and are often mistaken for plecos. They cling to rocks in the fast-moving mountain stream where they come from much like plecos cling to surfaces. Hillstream Loaches need well-oxygenated and well-filtered tanks and don’t do well with nippy tankmates or in tank with less-than-pristine water quality. They do eat some algae however, as well as other detritus and leftover sinking foods.

Otocinclus Catfish

Dwarf Suckermouth Catfish (Otocinclus sp.)

• PROS: Small size, safe for planted tanks, primarily algae-eaters.
• CONS: Can be sensitive to stress, can starve if they can’t find enough to eat.
• BEST SUITED AS: Algae-eating housekeepers in planted community aquariums.

There are a few very similar species that are commonly grouped together as Otocinclus Catfish (“Oto Cats”) or “Dwarf Suckermouth Catfish”. Most are brownish-grey in color with a black stripe but some like the Zebra Oto (Otocinclus cocama) have a more ornate pattern. These fish stay under two inches in length and are great for eating algae off of plants without harming the plants. They can be a bit finicky and sensitive though so only keep in a stable, healthy aquarium. They are also best kept in groups so plan tankspace accordingly.

Rubbernose Plecos (Chaetostoma sp.)

Spotted Rubbernose Pleco (Chaetostoma sp.)

• PROS: Moderately small adult size, eats some algae, community temperament.
• CONS: Not a primary algae-eater, can be bulky for very small tanks.
• BEST SUITED AS: A general bottom-feeder for community tanks over about 30-45 gallons.

Like the Clown Pleco, Rubbernose Plecos are some of the most common smaller plecos available. They also have a very familiar pleco-like appearance that many novice aquarists associate with algae control. They are not exclusive algae-eaters however; this is another omnivore that needs about equal parts meaty food and plant matter. These fish are pretty middle-of-the-road overall: moderate adult sizes, eats diet for about half their diet, neutral coloration, moderate temperament.

Freshwater Nerite Snails

Freshwater Nerite Snails (Neritina sp.)

• PROS: Colorful shells, safe for plants, small size.
• CONS: Limited availability, may reproduce, may be vulnerable to predators.
• BEST SUITED AS: Algae-eating grazers for small planted aquariums.

Nerite Snails are popular for saltwater aquariums but some species are found in freshwater as well. These snails are much smaller than some of the other less-suitable and more invasive freshwater snails like Apple Snails or Trapdoor Snails. They mainly eat smaller algaes like the ones that cause spots on glass but usually won’t harm plants. These snails also appear to bred less frequently in most aquariums than the more common Apple Snails. Make sure the ones you get are from freshwater; a saltwater Nerite will not survive being moved to a freshwater tank.

Freshwater Shrimp (Caridina sp.)

Several freshwater shrimp (Caridina sp.)

• PROS: Safe for plants, small size, can be kept in groups.
• CONS: Limited availability, vulnerable to predators, very small.
• BEST SUITED AS: Algae-eaters for planted nano tanks with peaceful or no other tankmates.

Small freshwater shrimp like the popular Cherry Shrimp and Amano Shrimp can be ideal grazers, especially for nano tanks (under 1-2 gallons). Some are clear, some are colored or have colored markings and they can be kept in groups. However, most of these shrimp are very small; you may not see them often and can’t be kept with anything remotely predatory.      

As always, the best algae-eater for your tank depends on its tankmates, the size of the tank, the water parameters and other such factors but hopefully this helps give you some alternatives to fish that may be too big or otherwise unsuitable to your needs. If you need more help in making your best choice or have a favorite of your own, feel free to comment below!