Catfish of the Month Right Arrow February 1997

Glass Catfish, Asian Glass Catfish, Indischer Glaswels (Germany), Indisk Glasmal (Sweden), Phantom Catfish, Thai-glasmalle (Denmark) - Kryptopterus vitreolus   Ng & Kottelat, 2013

Article © Julian Dignall, uploaded February 01, 1997.

Most people start keeping catfish for one or both of two reasons. The first is the misguided and widely perpetuated myth that they are all excellent scavengers and will compensate for over-feeding, under filtration, eat algae, eradicate snails and combat a multitude of aquatic evils. This is perhaps true, to varying degrees, of some catfish. I believe the other reason people start keeping catfish is that they are unusual. Glass catfish are one of the most unusual of an unusual bunch. You can see right through them.

I started with a trio of these fish. They were timid, but fed well and kept themselves to themselves. It struck me that these would be ideal fish to keep with Discus if they could tolerate higher temperatures that Discus prefer. I transferred my trio to the Discus tank successfully and increased the shoal to seven individuals who happily coexisted with the Discus, assorted Tetras and Corydoras also present.

True glass catfish are completely transparent. If you look at one through a magnifying glass you can see the heart beating within the silver reflective sac that houses all the fishes organs. This species is also unusual amongst catfish in that it is a midwater swimmer and is inactive at night. This is not your average catfish. Indeed, one of the most interesting (probably because unexplained) aspects of this odd fish is that almost immediately following death, the fish loses its transparency becoming milky white. This suggests that something Glass Catfish do while alive produces or maintains the transparent effect.

I have also seen the African Glass Cat - Parailia pellucida - labelled as the Glass Cat, so always keep your eyes peeled when you look at a tank of these fish for sale. While on the subject of keeping your eyes peeled, some of you may have noticed that we have labelled this fish with a scientific name different from that you find in most hobbyist books. It appears that the glass catfish has been misidentified for a long time now as Kryptopterus bicirrhis, this fish grows much larger (up to 10") and has more rays in its anal fin. It is quite possible that, at some point in the last 30 years or so, K. bicirrhis was the fish imported into the aquatic trade as the Glass Catfish. Given the lack of 10 inch Glass catfish around today it is probably safe to say this isn't the fish we encounter most frequently in the shops.

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