The Glass Catfish
Kryptopterus bicirrhus (Asian Glass Catfish), is unusual in a number of ways. As its name implies, it is transparent and some internal organs and the skeleton can be seen. It is also one of the few catfishes that is not benthic (bottom-dwelling), remaining in mid-water. The body is compressed, similar to most other pelagic fishes, rather than depressed. They are shoaling catfishes that must be kept in small groups, not individually, otherwise they will not feed. At rest, Kryptopterus remain in mid-water at a slight angle, head uppermost, but when swimming the body is horizontal. Water conditions are the key to their viability. The water should be crystal clear, well oxygenated, moderately fast flowing, and not too alkaline. Most planted aquaria are ideal for keeping glass catfishes. Flake foods are acceptable, but should bem supplemented with Daphnia, Cyclops, and/or freshly hatched mosquito larvae.
Some species of the family Mochokidae are often referred to as “upside-down cats” because they swim inverted. While many of the mochokids can swim in this way, less than half a dozen of the hundred or more species do so regularly. The advantage of swimming inverted is the ability to catch insects on the water surface, as the mouth is on the underside of the head, and one species, Synodontis nigriventris, also takes in atmospheric oxygen.
One of the species that stays upside-down on a long-term basis is Synodontis nigriventris. One of the smallest members of this family, growing to around 5 cm (2 in), it is peaceful enough for the community tank, but is best kept in small groups. Provide an overhang such as a rocky cavern, or better still a piece of wood with the overhang near the water surface. Here they will rest inverted, and be visible during the day. Most of their feeding activity occurs at dusk. Small surfacedwelling invertebrates such as mosquito larvae and pupae are recommended, though flake foodis also accepted. They have not been bred in captivity.
Most of the other mochokids grow larger, to over 20 cm (8 in), and can be too boisterous for most planted community tanks. There are, however, some species worthy of consideration. One of these is Synodontis angelicus (angelic catfish). Its distinctive coloration and markings make it a much sought-after species. Rarely do two specimens have similar markings. Some are spotted, others show light, reticulated bands, with all kinds of patterns in between. They can grow up to 20 cm (8 in).
An aquarium furnished with rocks providing many hiding places is required. Two adults in a confined tank may indulge in territorial battles, but in the larger aquarium this does not normally happen. For those who wish to include a catfish in their Tanganyikan or Malawian cichlid collection, a good choice would be Synodontis multipunctatus (Cuckoo catfish). The common name is derived from their breeding strategy: the eggs are released near oralincubating cichlids such as Tropheus duboisi when they are breeding, and the eggs of both species are picked up and cared for by the cichlid. Even as newly hatched fry, the Synodontis are cared for in the mouths of the cichlids. Water conditions need to be similar to those for Tanganyikan/Malawian cichlids (alkaline), and the tank furnished with rockwork. Many Synodontis, including this one, are sexable. Males have a short genital papilla near the vent.