How to raise Glass catfish (classified as Kryptopterus minor)

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Body
Adult size
Origin
Aquarium life and demands
Temperament
Diet and feeding
Sexing
Final note
Profile of the specie

Expert Advice by Mick, keeping fish since 1976

A guide on keeping Glass catfish by Mick Watson

Short introduction

The glass catfish has always been popular with fish keepers but sadly it is often kept in incorrect conditions as information about this species of fish is still a bit limited but the basic information can be found if you look closely around. The species covered in this article bears the Latin name of Kryptopterus minor, this species has many times been confused with a similar species that bears the Latin name of Kryptopterus bicirrhis, the confusion is understandable as both species look exactly as each other, the obvious changes are to be seen as they mature, the latter growing to a larger size and are rarer in the aquarium trade, often only being sold by the mentioned confusion.

Kryptopterus minor are also referred to by other common names such as the Phantom catfish or the Ghost catfish but the Glass catfish seems to be the most common name used, the origin of these common names is obvious to the eye as the fish are transparent and can appear to have a glassy sheen when swimming around the aquarium.

Clearly visible in the fish are the spinal column and the swim bladder, the other vital organs can be seen but are clumped together and not so easy to spot straight away. The glass catfish possesses barbels so care should be taken that these do not get damaged or infected, good husbandry in the aquarium should prevent this and make sure that any décor and substrate does not have any sharp edges.

Maximum adult size for these fish is just over 3 inches (7-8 cm) but in the aquarium the actual size reached may be slightly smaller.

Their natural habitat is the waterways of Indonesia where both glass catfish species can be found but sadly their numbers are starting to decrease as most specimens sold in the aquatic trade are wild caught and demand often exceeds the sustainable level that these fish can produce for successful colonies.

Caring for the glass catfish in the aquarium

The first major point to remember with these fish is the fact that they do demand a fairly high water quality to thrive, never add these fish to an aquarium that hasn't been cycled or the swings in the water parameters can affect their health.

The glass catfish tend to occupy the mid levels of the aquarium, sometimes they will swim to the upper levels once settled, so the choice of substrate is not too crucial, sand or gravel can be used but make sure that any gravel is rounded and does not have any sharp edges. The glass catfish definitely prefer planted tank set ups so make sure that there are plenty of plants in the aquarium, concentrate the planting around the edges and rear, some floating plants may also be beneficial as the glass catfish does not like bright lighting, floating plants will help to diffuse the light entering the aquarium. Wood or rocks should also be added as hiding places can be crucial, the glass catfish are a very timid species and hiding places will give them a greater sense of security, often encouraging them to swim around more in the open water knowing that they have an escape route if required. Keep the water flow to a medium pace as they cannot battle against a strong current and test the water on a regular basis to make sure that the quality is always kept high.

Glass catfish prefer acidic water conditions, a pH of 6.5 is ideal and the water should also be on the soft side, a GH of 10 or below is the target to aim for. The water temperature should be set at around the 25 °C mark (77 °F) but a degree either side of this should not affect the glass catfish in any way.

Only keep these fish with other peaceful species, they are very skittish and cannot tolerate and form of intimidation from other tank mates. Always keep the glass catfish in groups of at least 6 specimens, this will make them more secure and active as they feel at ease within a group, single specimens may become very solitary and hide a way a lot.

Feeding the Glass catfish

When first introduced to the aquarium the glass catfish may refuse a lot of foods and become very picky, this should dissipate in a short period of time if they are being kept in the correct conditions and they will learn to accept a variety of foods.

Live foods are the preferred diet such as white worms, mosquito larvae, brine shrimp etc. but in time they will also accept flake foods or even small granules. Always make sure that any uneaten food is removed from the aquarium as this can decay if left in there and spoil the water.

Sexing and breeding the Glass catfish

Unfortunately there are no proven records of these fish ever breeding in the aquarium and sexing these fish is impossible anyway as both sexes are identical. It is believed that they may be being bred in Asia with hormones but any details confirming this have yet to be sourced.

Overview

The glass catfish should always appear clear and bright in appearance, any dulling in the transparency could be the result of poor health, indeed with the mortality of the glass catfish their bodies take on a milky appearance. Always provide the best conditions and perform regular water changes to keep the water quality as high as possible. Open aquariums do not suit these fish, they need cover to feel safe, if not provided with this you will never get to see their natural behaviour and they may have shorter life spans due stress.