Fish, Tanks and Ponds

Fish, Tanks and Ponds
A comprehensive guide to fish

Kryptopterus minor

Glass catfish

Glass catfish, Kryptopterus minorGlass catfish, Kryptopterus minor
Photos by Andy Rapson


Kryptopterus: Greek, kryptos = hidden.
pteron: Greek, pterus = wing (fin).
The name refers to the lack of a dorsal fin in this species.

General Notes:

Kryptopterus minor is a sensitive fish which requires stable conditions of a high standard. There aquarium must be fully mature and without any trace of ammonia or nitrite, nitrates must be kept below 20ppm (mg/l) if the fish are to thrive.
Glass catfish tend to hide during the daytime particularly if the tank is brightly lit. Use lots of bogwood and plants to provide some hiding places which will help the fish to feel secure.
Never try to keep a single specimen or a pair, glass catfish are obligate shoalers or they suffer greatly from stress.
Due to their transparency these fish manage to hold everyone's attention because you can see their bones and internal organs and when the light does catch them at the right angle the fish exhibit a wonderful iridescence. Glass catfish aren't really for the beginner but neither are they impossibly difficult, with enough attention to detail and making sure that you provide them with the right environment these fish could live for five years or more.


Kryptopterus minor only has a small mouth and this obviously has an effect on its diet because their food is swallowed whole and not broken up. Small live inverts such as daphnia, cyclops, brine shrimps and pre cleaned tubifex worms make the ideal diet. Most individuals will accept frozen food and a few may even accept high quality flake or pelleted food, but this cannot be relied upon.


Kryptopterus minor is peaceful but quite a shy and timid species. The fish must be kept in a group of at least five other individuals and only with other quite fish.


There are no known external differences between the sexes.


Not known in the home aquarium.

Wild status

Near threatened. Kryptopterus minor has been widely over fished and its habitat in the peat swamps is being lost. Wild populations are showing a downward trend. Of the very few fish being sold in the aquatic trade the overwhelming majority are commercially bred and don't come from the wild.

Additional information

Kryptopterus minor has been confused with the far more widely available Kryptopterus vitreolus in the aquatic trade. As a result it is far more likely that your fish is actually the latter. Kryptopterus minor is almost completely absent from the aquatic trade.

Information at a glance

pH: 6 -7
dGH: 3 - 10
Temperature: 22 - 28°C (72 - 82°F)
Diet: Omnivore
Size: 7cm (3in)
Min tank size: 100 litres
Difficulty level: Intermediate
Aquarium type: Community
Swimming level: Lower & middle.

Distribution and habitat

distribution map for Glass catfish, Kryptopterus minor

Origin: Western Borneo.

Habitat: Peaty streams and swamps in lowland forests.


Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Siluriformes
Family: Siluridae
Genus: Kryptopterus
Species: K. minor, Roberts, 1989

Other common names:
Ghost catfish

Synonyms: none