Ghost Catfish (Kryptopterus minor)

Common Name:

Ghost Catfish.

Scientific Name:

Kryptopterus minor.

Family:

Siluridae.

Distribution:

This glass cat, the one most often seen in captivity, has only been found (to date, according to FishBase) in Indonesia; specifically, the western portion of the island of Borneo.

Diet:

These are either impossibly difficult to feed or they are among the best feeders, depending on the source. What is universally known is that these fish will gladly take a diet consisting solely of live foods. They love bloodworms, Tubifex, and mosquito larvae. They also feed well on brine shrimp. They reluctantly take commercially-prepared flakes and pellets, but may accept these more readily if the foods are delivered via current. It seems as though, like the ubiquitous cories, K. minor must sense the presence of food through its barbels, which would explain the necessity of current in delivering food that is commercially prepared.

Water Temperature:

73 degrees Fahrenheit seems to be an accepted bare minimum and 82 is generally accepted as the maximum temperature, but a range of 75-80 degrees seems to be most preferable to these fish.

Water Chemistry:

They come from acidic, slow-moving rivers that are heavy on vegetation but these rivers do have open spaces in which K. minor often congregates. Floating plants are often found in their home rivers, so these fish are used to diffuse light -- thus the lights must be subtle and probably diffused by duckweed and other such plants.

pH:

As they come from slightly acidic rivers, they need water with pH between 6.5 and neutral (7.0). They also need very soft water (5-19 dH). In captivity, they have shown a natural affinity for current in their water and they may not function properly without it.

Housing:

10 gallons for a small shoal of 2" fish, but I'd go with a well-planted 20 long for a shoal of six or so.

Sexing:

There is little known of the sexual morphology of the glass cats. Actually, there is very little known about the sexing or breeding of the entire family Siluridae save for one species, the giant wels (Siluris glanis). The glass cats have apparently been commercially bred on a small scale in Asia, but there has been little, if any, success within the confines of the aquarium. One author has suggested "bringing them into condition" in much the same manner as Corydoras spp. catfish. (That is, he suggests feeding richer foods and simulating the rainy season with copious water changes, etc., etc.) It is not apparent in his treatise if this works or not as it is merely a suggestion. What is obvious throughout many websites and books which mention this species is that they are not easy to breed at all.

Description:

These odd silurid catfish can attain a size of about 3". They are translucent (hence the name ghost cat or glass cat, as sometimes called) to the point where their skeletal structures are readily visible.

Behaviour:

A naturally shoaling fish, these current-loving fish do not do well when kept solitarily, even when part of a large community set-up. Most would recommend that the glass cat be kept in groups of four or more. They are generally midwater swimmers, and do not often touch the bottom, if they do at all. Thus, a glass cat spending most of its time on the bottom can reasonably be considered to be sick.

The fish is well-known for its nervousness in captivity, some of which may be mitigated by generously planting the background of its aquarium. K. minor does like to swim in open spaces, so the aquarium cannot be completely stuffed with plants, but their presence will make a world of difference in the attitude of the fish.

Tank levels:

Low Strata

Miscellaneous:

K. minoris one of the few fishes to have maintained a single scientific name throughout its presence in the hobby. Though the original glass cats of the aquarium may have been K. bichirris, few of the glass cats commercially available grow to the impressive length cited in accounts of their larger congener. Thus it is likely that this fish, although only formally described in the late 1980s, is the glass cat that has been a staple in aquarium stores for decades. Glass cats are unique for many reasons. The first is obvious -- the transparency, which allows their skeletal system to be seen by all and also makes their beating hearts externally visible. What seems unusual with the transparency is that they turn a pasty white at the time of their death. Not much research has been done but, empirically, it seems as though the transparency is controlled by some organ in their bodies. Also, they are midwater swimmers and diurnal fish, so they are far from the typical catfish. Finally, the glass cats aren't really like the other Silurids. For one, they do not eat many fishes (save for a few fry). Of course, K. minor is also one of the few Silurids that are apropos for a home aquarium as it is among the tiniest members of the family. It is amazing that this fish is closely related to one that can attain the stunning size of 18 feet!