That Fish Blog – Aquarium Advice and Information

Hello, Frank Indiviglio here. 

Known by as many as twenty common names, including rough fish and Chinese high-finned banded shark (Myxocyprinus asiaticus), this unusual Chinese import is the subject of much confusion…both as to its natural history and care in captivity.  One thing is certain – this often over-looked oddity is among the hardiest and most interesting fishes that one might add to an outdoor goldfish or koi pond. Check out a picture here.

Natural History

Chinese sailfin suckers are believed to be endemic (found nowhere else) to the Yangtze and Minjiang River Basins in China.  Yet rumors persist that the fish is native to Japan as well, and for a time the populations there were considered to be a distinct subspecies.  Most authorities now consider the subspecies status to be invalid, but there is no consensus as to the origin of the animals living in Japanese waters (I imagine they are feral, introduced from China).

Recent studies indicate that this fish makes extensive breeding migrations, and that its continued survival in China is threatened by dam building and over-harvesting for the food trade.

Care in Captivity

The confusion as to the care of the Chinese sailfin arises from the lack of basic information concerning its natural history.  Fueled perhaps by its “exotic” appearance, this fish is generally sold as a tropical species for inclusion in home aquariums.  In truth it favors water of 62-70 F (although it is tolerant of higher temperatures), may reach 24 inches in length (39 inches by some accounts) and can over-winter under ice in water of sufficient depth.

Chinese sailfins are, therefore, much better suited to an outdoor pond than an aquarium.  Clad in tones ranging from golden-brown to rusty-pink (breeding males are red, females dark purple) and with 3 broad, dark vertical bands, an enormous triangular dorsal fin and comically small head, this bottom-dweller is quite a sight! 

It does best in groups, is peaceful in the extreme, and fares well on a diet of Koi or Goldfish Pellets and Algae Wafers  (they are decidedly vegetarian in their food preferences).

Other Unusual Pond Fishes

Chinese sailfin suckers present no difficulties over and above what you might encounter in keeping koi or goldfish outdoors, and will add a great deal of character and interest to your pond. 

Native fishes also present fine opportunities to expand upon your collection of “outdoor fishes”…some mix well with typical pond fish, and without exception all are very interesting.  The cutlips minnows and burbots pictured here, while not very colorful, are fascinating to keep and very hardy.  Please look for my articles on keeping native fishes in the future.

Further Reading

A synopsis of what little field research has been done with this fish is presented in Current Zoology.

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

Hello, Frank Indiviglio here.

Please see Parts I and II of this article for general information and for details concerning the care of elephant nosed and butterfly fishes.

Dwarf Clawed or African Dwarf Underwater Frog, Hymenochirus boettgeri, H. curtipes

This tiny (males to 1 inch, females to 1.4 inches) aquatic frog is a real pleasure to keep.  It is perpetually on the prowl, sticking its pointed little head into every nook and cranny in its ceaseless search for food.  A group so engaged is really quite comical to behold…they look like nothing so much as squadron of tiny, flattened divers!

Habitat and Habits

Dwarf clawed frogs move slowly about the aquarium bottom and among the plants, and save “free swimming” for trips to the surface for air.  In deep aquariums, they do best when provided with “ladders” to the surface in the form of (preferably live) plants.  They are at their best in heavily planted aquariums, and will utilize every square inch available to them. 

Small size and bold demeanors render these frogs ideal observation subjects. It is quite easy to provide them with a habitat in which they will reveal to you nearly all of their natural behaviors, and captive reproduction is not uncommon.  Dwarf clawed frogs are not favored aquarium animals in the USA, due largely to the fact that they are usually kept improperly.  Typically housed in bare tanks with active fishes that out-compete them for food, they usually expire in short order. 

Feeding Dwarf Clawed Frogs

In addition to dense cover, dwarf clawed frogs need a varied diet of small, live invertebrates.  Blackworms can account for up to 75% of their food intake, supplemented whenever possible with live brine shrimp (brine shrimp alone are not an appropriate diet), whiteworms, bloodworms, mosquito larvae and similarly-sized aquatic organisms.  Newborn guppies may be taken by particularly large individuals.  I’ve had my best breeding results when I provided my frogs with occasional meals of pond-seined fairy shrimp and other tiny invertebrates.

I have not had much success in inducing dwarf clawed frogs to accept non-living food items, but others have reported good results with some individuals.  I suggest that you feed them as described above, but experiment with Reptomin Select-A-Food  (freeze dried and pelleted components), freeze-dried fish foods  (mysis shrimp, daphnia, bloodworms) and frozen mosquito larvae.

As dwarf clawed frogs feed largely by day and elephant nosed fishes by night, competition for live blackworms is rarely a problem.

A Unique Hunting Strategy

Dwarf clawed frogs use a suction-based feeding technique, unique among amphibians, to capture their prey.  The tiny hunters lunge forward while extending the front limbs and opening the mouth, after which the body is recoiled.  Like other members of the family Pipidae (African clawed frogs, Surinam toads), dwarf clawed frogs are tongue-less.

Hybrids and Feral Frogs

Only Hymenochirus boettgeri and, to lesser extend, H. curtipes, appear in the trade; there is some evidence of hybridization between the two.  H. boettgeri has been introduced to Florida and is apparently well established.

An Important Distinction

It is important that you are able to distinguish this frog from young African clawed frogs (Xenopus laevis).  The two are frequently housed together in pet stores….Xenopus grows quite large and will consume smaller frogs, fishes and shrimp.

In dwarf clawed frogs, the appendages of all 4 limbs (fingers and toes) are webbed; Xenopus possesses webbed feet only.  Dwarf frogs are also more flattened in body form, and their heads are very narrow, nearly “pointed”.

Giant African Fan Shrimp, Atya gabonensis

This stoutly-built West African native is bound to become more popular as time goes on.  Built more along the lines of a crayfish than a shrimp, yet completely benign toward tank-mates, it feeds by sweeping food into its mouth with feathery appendages.  Fan shrimp are quite social in nature, with groups often sharing the same shelter even when others are available. 

The Importance of Shelter

I have found African fan shrimp to be compatible with the other animals mentioned in this article, provided that they have access to secure shelters.  They seem to be very much “home oriented”, and become quite stressed when their retreats are disturbed in any way. 

Be sure to supply your shrimp with caves and other such hideaways that will not be disturbed by foraging elephant- nosed fishes (the other species pose no concerns), and do not move the shelters once they have been occupied.  Small rock dens  or Mopani wood shelters  are ideal.

Please see my article on the Natural History and Care of African Fan Shrimp  for husbandry details.

I was recently told of an unusually large (possibly 8 inch) fan shrimp that was residing in a local pet shop.  I went to see the animal, only to find that it had expired and had been discarded.  Please write in if you have observed fan shrimp larger than 5 inches or so – we have a great deal to learn about this animal…perhaps there is more than 1 species in the trade.

Further Reading

You can read more about the dwarf clawed frog and its relatives at http://research.amnh.org/herpetology/amphibia/names.php?taxon=&family=&subfamily=&genus=hymenochirus&commname=&authority=&year=&geo=0&dist=&comment=.

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

Frank Indivlgio here.

Check out: A Community Aquarium for Fishes, Shrimp and Frogs – West African Oddities – Part 1, to read the first part of this article.

Water Quality

Great care must be taken with water quality…in fact, the elephant noses’ sensitivity is such that they have been used to monitor water quality in industrial situations.  They should only be introduced to well-cycled aquariums, and the test kit mentioned earlier should be employed regularly to test ammonia levels and other water quality parameters.  That being said, when cared for properly the elephant nose will reward you with many years of enjoyment…I know of no one that regrets adding them to their collection.

African or Fresh-Water Butterfly Fish, Pantodon buchholzi

Inhabiting the same waters as the elephant nose and well suited to the same aquarium is the African butterfly fish.  Living on the surface and active by day, the butterfly fish is the elephant nose’s polar opposite.  The two rarely interact and nicely illustrate diverse and very unusual survival strategies. 

An Unusual Appearance and Lifestyle

Wing-like pectoral fins lend this oddball its common name, and long rays trailing down from the pelvic fin add to its unusual appearance.  When viewed from above it does indeed bring a butterfly to mind, but it is more likely a dead, floating leaf that the fish is imitating. 

This well-camouflaged predator spends its life floating quietly on the surface, where its appearance and upturned mouth suit it admirably as a specialized hunter of terrestrial insects that fall into the water.  In West African rivers teeming with competitors, the butterfly fish, much like the elephant nose, has evolved a unique way of exploiting a food source not available to most other fishes.

Feeding African Butterfly Fishes

African butterfly fishes feed only at the surface and will not dive for food.  While most individuals will accept flake and freeze dried diets, they really come to life when offered live insects.  Their reactions at such times will leave you with no doubt as to their dietary preferences.

Being highly evolved to feed upon a unique food source (land-dwelling insects), butterfly fishes do best when provided with the same in captivity.  They will take a variety of foods, but I have found them to fare best on diets comprised largely of small live crickets, newly molted (white) mealworms, mealworm beetles, wax worms and wild caught moths, spiders and other invertebrates (the Zoo Med Bug Napper  is a very useful insect trap). 

Canned insects  provide a convenient of increasing dietary variety.  Zoo Med’s Anole Food  contains small freeze dried flies – another great way to provide a natural food item to this most interesting denizen of tropical West African waters. 

As you might gather from the foregoing, butterfly fishes rarely thrive in typical community aquariums.  However, when fed properly and established in an appropriate environment, they are very hardy – living well in groups and not at all shy about revealing their unique hunting skills.  The powerful pectoral fins enable this fish to skitter across the surface when threatened and to jump well, so be sure that your aquarium is securely covered.

Further Reading

Please see my article The Use of Electrical Impulses in Elephant-Nosed Fishes  for further information on a newly discovered mode of elephant nosed fish communication.

You can read about the natural history of the African butterfly fish at http://www.fishbase.com/Summary/speciesSummary.php?ID=2075&genusname=Pantodon&speciesname=buchholzi

Next time we’ll take a look at some interesting invertebrate and amphibian members of the “West African Oddities Community Aquarium”.  Until then,   please write in with your questions and comments.  Thanks, until next time, Frank Indiviglio.

Hello, Frank Indiviglio here.

The subjects of this article are often sold in pet stores as “curiosities” to be added to aquariums housing typical tropical fishes.  Unfortunately, due to their unique dietary requirements and feeding methods, none do well in such situations.  As most hobbyists are unaware of their fascinating behaviors, tanks are rarely set up solely for these creatures, and most perish in short order. 

I recently set up a tropical West Africa themed exhibit for a public aquarium, based on similar tanks I have maintained at home and at the Bronx Zoo.  It was a big hit and generated many inquiries from visitors who wished to have a similar aquarium in their homes. 

The aquarium I’ll describe here is similar to that exhibit.  It houses animals from the same region of Africa, and includes two of the pet trade’s most interesting and overlooked fishes, a social shrimp and an active, aquatic frog.  All follow different lifestyles and utilize unusual feeding methods, yet they co-exist very well.

General Considerations

The animals described below hail from West Africa, and all prefer heavily planted aquariums maintained at 78-80 F.  They are quite sensitive to water quality, so be sure to choose a filter that is of an appropriate size for your aquarium, but avoid strong currents (from the filter’s outflow) within the tank.  A comprehensive water test kit  should be used regularly to assure that pH is held between 6.8 and 7, and that the water is moderately soft (water softness is not a major concern, but is best monitored).

Due to the feeding habits of the elephant nose (see below) and the desirability of establishing a lush growth of plants, I suggest that you use Porous Clay Gravel as a substrate.

Peter’s Elephant Nose or Elephant-Nosed Fish, Gnathonemus petersi

This first recommended member of the aquarium is truly interesting in appearance and behavior.  It uses the greatly extended lower jaw from which its common name is drawn to root in the substrate for aquatic worms and insects, its main food source.  Organs near the tail discharge electrical impulses that allow the elephant nose to navigate, hunt and, according to recent research, to communicate (please see the article referenced below).

Feeding and Observing the Elephant Nose

The elephant nose is a confirmed live food specialist, and rarely feeds before nightfall…hence it is always out-competed for food when kept with swordtails, platys and other typical community fishes.  A heavy growth of live plants will encourage it to move about by day; Moonlight Bulbs  are great for use in observing nocturnal behavior. 

Although only small specimens are usually seen in the trade (adults do not ship well at all), the elephant nose can reach 10 inches in length – a group of adults foraging in a large aquarium is a very impressive sight.  Live blackworms can form the foundation of their diet, but you should endeavor to include live bloodworms, glassworms and other such invertebrates regularly.

Click: A Community Aquarium for Fishes, Shrimp and Frogs – West African Oddities – Part 2, to read the rest of this article.

Frank Indiviglio.

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.