That Fish Blog – Aquarium Advice and Information

Hello, Dave here.

When most people think of giant fish, they imagine some behemoth dwelling at the bottom of the ocean. While the world’s oceans certainly have their share of massive fishes, most people are probably unaware of what may be lurking in the freshwater lakes and rivers of the world, some of them right here in the U.S.

What brought this blog to mind was a recent article that I came across that chronicled the recent capture and tagging of a Giant Freshwater Stingray by British Angler and Scientist, Ian Welch. The Stingray that Ian Caught is thought to be one of the largest fish ever caught of rod and reel. The Giant Freshwater Stingray (Himantura chaophraya) was caught in Thailand’s Maeklong River while on a research expedition. This stingray was estimated to be over 265kg (584lbs) and over 3.5m long. Some reports exist of these giants reaching sizes of 16.5 feet (5 meters) long and weighing up to 1,320 pounds (600kg). That is a big fish!

Not to be outdone is another giant native of Thailand, the Mekong River’s Giant Catfish (Pangasianodon gigas), which can reach lengths over ten feet and 650 lbs pounds. Both of these Thai giants are endangered species, and have been overfished for many years.

China has its share of freshwater giants also. One of the most bizarre giant freshwater fish of the world is the Chinese paddlefish (Psephurus gladius). This giant has been said to reach an amazing 23 feet (7 meters) in length and weigh up to half a ton (450kg). Another Chinese monster fish is the Giant White Sturgeon. The Giant White Sturgeon, who along with the Paddle fish is native to the Yangtze River, reaches 12 feet and weighs more than 950 pounds. Sadly, both of these fish are on the brink of extinction in China due to overfishing, pollution, and loss of habitat.

The Americas have their share of freshwater giants as well. Native to the Amazon River basin in South America, the Arapaima (Arapaima gigas), can reach lengths of 10 feet and weighing as much as 400 pounds or more.

North America has a few noteworthy big fish, too. The Alligator Gar can weight up to 300 pounds and is commonly found along the Mississippi River basin, as well as many other southern states. They are very common to Florida’s Everglades. The Alligator Gar can reach up to 10 feet, and some historical accounts have them even larger than that!

North America also has some large sturgeon species native to its waters. The White Sturgeon can be found in the rivers and estuaries of western Canada, and Northwest United States. I am not sure if this is the same species that is found in China, but in 2005 an 11 foot, 1000lb specimen was caught in British Columbia’s Frazier River.

Lake sturgeons (Acipenser fulvescens) are common to the great lakes, and many other large cold water lakes in northern states, These fish have many accounts of specimens topping six feet (two meters) long and weighing over 200 pounds (90 kilograms).

So as you can see, there are quite a few large freshwater fish, you don’t need to explore the far reaches of the ocean to find them, some may be in your neck of the woods.

One thing that I must also mention is that some of these fish are sometimes seen for sale as aquarium fish. Obviously, none of them are suitable for aquariums and should not be kept as such.

Until next time,
Dave

Giant stingray image: guardian.co.uk
Arapaima Image: Wikipedia

The Marine Bio staff That Fish Place gets a lot of questions about husbandry of fish and inverts in aquariums. When adding any new inhabitant to an aquarium we recommend researching the conditions, max size, and temperament of the species you are interested in to ensure that it will be a good fit for your tank and the other creatures you may already be keeping. And, as always, quarantining new additions in a separate aquarium is highly recommended.  If in doubt, we’re always here to answer any questions you may have so you and your aquarium continue to stay happy!

 One question recently submitted was from Al in New York:

 I’m going to be starting up my 55 gallon set-up with blue rams. My questions are what will make good tank mates? What water conditioners might I need? Should I use live plants, and if so which do you recommend? How many rams should I add?

 Marine Bio Responded:

There are several fish you can keep with rams. Lemon tetras in a school of 6-10 would be nice. Serpae tetras in a large school of 8 to 10, or Brilliant rasboras in a similar school would also work well. These are fish (introduced gradually) that I would start with once the tank is established. Rams should not be added to the tank for at least 2 to 3 months after the introduction of your first fish. So you can maybe start with 6 Serpaes or Brilliant rasboras, and let the tank run for with nothing else added until the cycle is complete.

During this time, you can certainly add plants if you wish, but do not add more fish. I am a proponent of live plants in aquariums. They make for a beautiful and healthy environment, and many fish will do very well in a planted tank that is similar to their native waters. Plants that you can add may include Rotala, Ruffled swords, Ozelot swords, dwarf sagittaria, and Bacopa. These are all nice plants to start with, and there are others you may prefer, it is all according to taste and the lighting and conditions you present. Just make sure you add Flourish Iron or a similar product to your tank to help your plants to stay healthy.  

After you cycle your tank with the tetras or rasboras, you can add some Corydoras Catfish in school of 5 or 6 to help keep the bottom clean. Some smaller pleco species may also be considered.  Rubbernose plecos, for example, are great algae eaters in planted aquariums, as are Bristlnose and Medusa plecos. Gold nugget plecos and Queen Arabesque plecos would also work, and they are really attractive. When you are ready to add rams, I would think a small group of 5 or 6 would work out great for you, maybe 1-2 males and the rest females.

Water conditions? Well, rams prefer warm, soft water. So you want your temperature to be in the range of 80 to 82 degrees, and your pH should be around 6.5 to 6.8. You may need a buffer to maintain the keep the water at this pH and there are several available to choose from and keep on hand for water changes and maintenance including Seachem Discus Buffer.

Hello, Frank Indiviglio here.

With their ridiculously long “noses” (actually an extended jaw), secretive ways and unique feeding strategies, the elephant-nosed fishes have long been aquarium favorites.  All of the 200+ species discharge electrical pulses from specially-modified muscle cells near the tail. 

The most commonly kept species, Peter’s elephant nose, has been shown to vary the strength, frequency and duration of these discharges.  Doing so helps this nocturnal fish to navigate and hunt in the turbid West African rivers it inhabits.

Using Electricity to Choose a Mate

Recently, researchers at Germany’s Potsdam University have shown that a related species, Campylomormyrus compressirostris, identifies potential mates by the characteristics of their electrical discharges. 

In laboratory tests, gravid females responded to the signals of males of their own species, but ignored those of a closely related fish that shares their natural habitat.  In this way, they are able to locate a mate of the proper species, even when surrounded by similar fishes in murky water at night.

It is theorized that Peter’s elephant nose also uses electricity as a form of communication and mate recognition.  Certainly, watching them avoid obstacles and locate buried blackworms in an aquarium at night, it is easy to see how completely they rely upon their electric-generating system.

Keeping Elephant-Nosed Fishes

Although very popular, elephant-nosed fishes require special care and rarely do well in community aquariums.  I recently set up an exhibit housing a group along with some other of their interesting West African neighbors – butterfly fishes, giant filter-feeding shrimp and dwarf clawed frogs.  Please look for an article on this exhibit and their general care soon.

Please Note:  The “trunk-less” fish pictured with the elephant noses is not the victim of an unfortunate accident but rather a related species, the baby whale or stoneroller, Pollimyrus isidori.  They are also quite interesting and do, if you have an active imagination, somewhat resemble (very!) small whales.  I’ll address them in the article mentioned above.

Further Reading

Belgium’s Africamuseum has posted an interesting article on the Peter’s elephant nose (Note: the photo appears to be of a deceased fish…they are much more attractive than pictured here!): http://www.africamuseum.be/museum/treasures/gnathonemus%20petersii

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

Brandon here. Many aquarists that come through our fish room will ask what we recommend as algae eaters for their reef.  The answer is usually the same: snails, hermit crabs, or maybe a lawnmower blenny.  One of the most efficient algae eaters found on the reef is usually overlooked, the sea urchin.

Sea urchins are relatives of starfish and sea cucumbers, belonging to the phylum Echinodermata.  They are generally covered in hard spines for protection, little clawed arms called pedicellariae which are used to remove debris and detritus from the urchins’ skin and can also aid in protection, and tube like feet used for moving across the substrate.  Their mouths are surrounded by a structure called Aristotle’s Lantern, which is used for scraping rock and breaking food apart.  The Aristotle’s Lantern is what makes some urchins such efficient algae eaters.

While not all sea urchins eat algae, and not all that eat algae are desirable for a reef tank, there are a few that would make a great addition to the aquarium.  The Variegated Green Urchin, Lytechinus variegates, stays relatively small and clears live rock of virtually all types of algae.  One urchin that we use in some of our display tanks here at the store is the Tuxedo Urchin, Mespilia globulus.  These urchins also remain relatively small and do a number on different types of algae.  Another extremely efficient, algae-eating urchin is the Longspine Urchin, Diadema setosum.  These can grow very large, and have spines capable of puncturing skin and leaving a painful injury.

 Here are some urchins to avoid in the reef tank.  Rock-boring Urchins, Echinometra lucunter, do little to clean up algae.  They spend most of their time chewing holes in live rock.  Priest Hat Urchins, Tripneustes gratilla, are generally considered reef safe, and will even do some scavenging, but they can also grab immobile fish and inverts for dinner.  One urchin that we do not carry here at That Fish Place, the Flower Urchin, Toxopneustes pileolus, is very beautiful but can inflict a potentially deadly sting.  It is covered in what appears to be little flowers, but are actually pedicellariae.  These specialized pedicellariae have three jaws on the tip, each of which is hollow and filled with venom.  Upon contact they snap shut and inject venom into the skin, which causes extreme pain and even muscle paralysis, which could drown an unsuspecting diver.

Urchins are not for everyone.  While they will clean up most types of undesirable algae, they can also scrape coralline algae from the rock work, leaving it white and bare.  They also require good water quality in respect to temperature, salinity, and other factors.  Always be sure of the urchins’ specific requirements and adult size before purchasing.  Whether you have a reef tank or not, urchins can make very interesting additions to the aquarium.

Back with some more FAQs sent to our Marine Bio staff.

Thurman wrote:

I’m raising a baby silver Arowana.  I would like to know, what meds do you recommend to keep in stock, How effective are vitamins, and are any water treatments needed besides prime or salt ? What is black water?

Marine Bio answered:

Some Meds I recommend keeping on hand are Kanaplex, Sulfathiazole, and Quick Cure.

These products treat a wide spectrum of diseases and are all very effective. Beyond all things, water quality and temperature stability will be the most important things for your arowana. Vitamins are completely subjective. Some people use them. I personally do not. A good food will have everything he needs to stay healthy. Try to get him off of live food as soon as possible. When they are small, floating pellets work pretty well. Just make sure to get small ones.

Black water is the term for the coloration and conditions found in parts of the Amazon River. There are natural organics, acids and tannins that leach into the water from wood and soil to create very soft water that is colored almost like a dark tea. There are several products that can simulate these conditions for you if you prefer.

Ryan wrote:

I currently have a 30 gallon bow-front salt water tank with one Condylactis Anenome, some Mexican turbo snails, live rock and blue legged hermit crabs. I wanted to transfer everything into a 75 gallon tank. But I just lost all of my fish to ich. Should I use new crushed coral, or use the old stuff from my little tank? What would be the safest way to know I won’t get ich again? I will set up a hospital tank, but I don’t want to have the same problem in my 75 gallon.

Marine Bio Responded:

Since you have recently had ich in your 30 gallon tank, there can always be the chance for another ich outbreak since the encapsulated cysts can hang around in your tank for several weeks. If you transfer the sand from your 30 gallon to your 75 gallon, you increase the chance of having another outbreak.  If you start with new sand, and add a new fish without quarantining them, you still have a risk of getting ich in that tank as well.  If it has been over a month since you have had fish in your tank, I would probably go ahead and add the sand from your 30 gallon tank just because of the good bacteria that is thriving in it. It is up to you if you want to buy brand new sand and start over, or use what you have and add new to it.  There are pros and cons both ways.  Ich is very tricky, the best thing you can do is quarantine and keep the conditions in the tank pristine.  Poor water conditions and stress may prompt an ich outbreak too.  You may want to keep meds on hand in case of any problem, just be sure you’re using a reef safe medication or remove your inverts to treat in the event of a recurrence.