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Related Catfish FAQs: Banjo Catfishes, Identification, Behavior, Compatibility, Selection, Systems, Feeding, Disease, Reproduction,

Related Articles: Catfishes.

/A Diversity of Aquatic Life

The Banjo Catfishes, Family Aspredinidae

Bob Fenner

Known for a few regular offerings in the aquarium interest, banjo catfishes are the epitome of... well, laziness or at least inactivity. Honestly, it's hard to tell whether these dun-colored extremely dorso-ventrally flattened fishes are alive or not. They barely get up to move until food practically drops on them! The family Aspredinidae is entirely South American, with a few (though not used as aquarium specimens) occurring in brackish to marine environs. There are 32 species in ten genera in total.

The family is typified as being naked (lacking scales) though having bony tubercles as body armor (the group is named for "aspron", a Turkish coin for its members hardness, shape and color). Aspredinids lack adipose fins, are depressed top to bottom and are mostly small (less than six inches, though one does approach sixteen inches in total length).

Regarding this family's systematics: recent literature may prove challenging concerning discussion of original descriptions and changes in genera... due to precedence issues in the 19th century. In dealing with these fishes identification you are strongly encouraged to either settle (long distance, sight-unseen) on a particular reference work ("look at page #, row #...) and in person, make your own determinations. Here I've gone with the current Fishbase.org identifications.

Some authorities split this family into two separate ones, others into two subfamilies... the Aspredininae (or -idae) are the whip-tail banjo cats, are larger (8-16 inches) with much longer, thinner posterior regions of their bodies and long anal fins. Several of these are brackish to freshwater and prefer neutral to alkaline water of good oxygen content. The Bunocephalinae (or -idae) are the "true" banjo cats and include most all the species that make it into our tanks. These fishes are completely freshwater.


Banjo catfishes must either be kept in specialized "species tanks" or housed with very passive (i.e. non-competing) tankmates. They are not able to compete for foods with fast moving, make that moving fishes and invertebrates.

Water quality. Most species prefer slightly acidic water (pH 6.5-5.8), of moderate tropical temperature (seventies to low eighties F.), and soft to medium hardness (to 15 DH).

Tanks, substrates, lighting: Aquariums are best large though these fishes are not active, their feeding habits can easily leave a system messy, with concomitant water quality issues. They prefer soft substrates like fine sand, even peat, to dig into, and low lighted settings (these fishes are nocturnal). Do take care to supply a relatively open space to condition your banjo cats to feed at... one with not much substrate... and it is best not to provide much sand/gravel period if you want to observe these cats much as they are prodigious burrowers and will spend a great deal of time buried out of view. Live plants are best blind-potted and otherwise of floating types.

Filtration: should consist of inside or outside power filters. Undergravel is not a good idea on a few counts. The fine substrate and digging catfish will render it ineffective, and with so much meaty food being offered there is too great a risk of bacterial proliferation with its consequent ills. A maintenance item of note is the Aspredinids production of copious amounts of "skin" that is regularly shed. Do include regular gravel vacuuming with your water changes to remove this material.


Should be occupants of other than the bottom and not so fast feeders as to deny the bottom-living banjo cats of their foods. Small tetras, Gouramis, danios, easier-going barbs... as long as these are more than mouth size (and the Aspredinids do have wide mouths!) should be fine. Loaches and small catfishes of other families are too likely to eventually become meals. Sands (1996) mentions the production of a chemical defense at the base of these fish's pectoral fins that inspires a "flight" reaction in other fish species. Another good reason to keep these cats either on their own or in large, well circulated and filtered systems.

Some Species of Aspredinids You May Find:

Subfamily Aspredininae: The whip tail or eel banjo catfishes

Aspredo aspredo (Linnaeus 1758), the Whiptail Banjo. Western Atlantic: lower portions of coastal rivers from Venezuela to northern Brazil. To 15 inches in length. Brackish and freshwater. Females carry eggs attached to underside (thought to aid in aeration).
Platystacus cotylephorus Bloch 1794, the Whiptail Banjo. Western Central Atlantic: Venezuela to northern Brazil (including the lower portions of coastal rivers). To about a foot in length. Brackish and freshwater. Water Cond.s: pH 6-8.2, DH 12-35, temp. 22-25. Spawns in brackish water.

Subfamily Bunocephalinae:

Bunocephalus amaurus Eigenmann 1812, the Camouflaged Banjo Cat. South America: coastal rivers between the Orinoco and Amazon mouths. To 12 cm. in length.
Bunocephalus coracoideus (Cope 1874), the Guitarrita or Banjo Cat. South America: Amazon River basin. To 11 cm. in length. Water Cond.s: pH 6-8, DH 5-19, temp. 25-28 C. Spawns by laying eggs (4000-5000) in a sandy depression (differs from other Aspredinids in that the female does not carry the eggs)
Bunocephalus knerii Steindachner 1882, the Ecuador Banjo Catfish. South America: western Amazon River basin. To 13 cm. in length. Water Cond.s: pH 5.8-7, DH 8-15, temp. 20-25 C.
Bunocephalus verrucosus (Walbaum 1792), the most common Banjo Cat. South America: rivers of Guyana and the Amazon River basin. To 9.5 cm. in length. Water Cond.s: pH 6.8-7.5, DH 8-15, temp. 20-24 C.


Though banjo cats can be trained onto dried, prepared sinking foods, they only do well on diets composed of live, meaty foods. Worms of various sorts depending on the size of your fish, insect larvae, live brine shrimp... are what we're talking here. Chopped meaty foods are also well-accepted through conditioning, offering these a bit at a time, along with live/fresh. Foods are principally consumed during the night, when these fishes are active, so it is advised to offer them right at "lights out" or slightly after.


About Netting These Fishes: Don't

Aspredinid catfishes produce sound by stridulation; rubbing their pectoral fins along their sides (the cleithrum bone). Their "pecs" are also useful for wedging, holding them into spots (through a lock-able mechanism in their rotation)... but they're also a source of real trouble for hobbyists who insist on netting them. Their spines get very easily caught in netting... and there is no need to use nets with these fishes... just reach in and lift them into a bag placed underwater.


Aspredinids are egg layers with some species having shown brooding behavior. There are accounts of captive spawning and rearing of young (see below). In general, the aspredinines attach their eggs to the female whereas the bunocephalines dig a spawning pit and males guard them. Young hatch out in about three days at 28 C. with the parents and conspecifics ignoring them.


For the true catfishionado there are no real reasons to offer for dedicating a system to keeping these fishes. They are interesting, though not active or spectacularly colored or marked. Well-deserving of having their own specialized set-up and maintenance.

Bibliography/Further Reading:

Catfishes on the Internet: http://phylogeny.arizona.edu/tree/eukaryotes/animals/chordata/actinopterygii/siluriformes/siluriformes.html

Planet Catfish: http://www.planetcatfish.com/core/index.htm

Burgess, Warren E. 1989. An Atlas of Freshwater and Marine Catfishes: A Preliminary Survey of the Siluriformes. T.F.H. Publications, Inc. NJ. 784pp.

Burgess, Warren E. 1990. Banjo cats playing a different tune. TFH 1/90.

Nelson, Joseph S. 1994. Fishes of the World, 3d ed.. John Wiley & Sons, Inc. NY. 600pp.

Petrovicky, Ivan. 1987. A successful spawning of Bunocephalus bicolor. Although definitely not the winner of any piscine beauty contest, the banjo cat Bunocephalus bicolor is an interesting fish and now one whose spawning habits are finally known. TFH 3/87.

Sands, David D. 1986. Catfishes in aquaria, pt 2. The Aspredinids or "Banja-men". TFH 11/86.

Sands, David D. 1992. New notes on banjos. FAMA 8/92.

Taylor, Edward C. Incidental imports. Whip-tailed banjo catfishes. TFH 2/83.

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