Chaca chaca

India, Nepal, Bangladesh and Indonesia.

It inhabits both large and small bodies of still or slow-moving water, where it lies hidden amongst leaf litter and mulm.

This species does not require much space for its size. An aquarium measuring 36" x 12" x 12" (90cm x 30cm x 30cm) - 80 litres is adequate for a single specimen.

A dimly-lit tank suits this sedentary species. The use of a soft, sandy substrate is also recommended as the fish often bury themselves. Most plants will not do well in such conditions, but tolerant species that grow attached to decor, such as java fern and java moss can be used. The addition of some beech twigs and dried oak or beech leaves will help to simulate the natural habitat of the fish.

Temperature: 22 – 25 °C72 – 77 °F

pH: 6.0-8.0

Hardness: 4-25°H

It is sometimes possible to wean young specimens onto dried or meaty frozen foods. However, many specimens refuse anything but live food. Small fish, river shrimp and earthworms can all be offered.

A highly predatory species, C. chaca is best kept alone. It will consume almost any fish that strays close enough to its capacious mouth and is capable of swallowing prey items almost as big as itself. In large, deep aquaria it may be possible to keep it with fast-swimming species that live high in the water column, but even this carries risks. It can however be kept with others of its own kind with no problems.

Males are longer and slimmer than females.

This species has been bred in aquaria. A group of 4 fish spawned in a length of 3" diameter tubing, with a male fish guarding the eggs over the 3 day incubation period, after which no further parental care was observed. The fry became free swimming after 7 days. Presumably they were raised on small live foods.

Chaca are unsuitable subjects for the general aquarist, but are quite popular among lovers of oddball species. This species is very similar in appearance to the closely related C. bankanensis. However, it's usually a bit lighter in colour than its relative and possesses small hooklets on the lower lip and body that are not present in bankanensis. It's a true master of disguise and is also known as the angler catfish, due to its ability to use its barbels as a kind of lure. These can be moved in such a way as to simulate the movements of a worm when a potential meal approaches. The unwitting prey is attracted to this apparent feast, only to be grabbed in a lightning-fast movement by the catfish when it strays too close.

C. chaca is rarely observed moving around the aquarium during daylight hours, though it sometimes leaves its position to forage under cover of darkness. The use of a red light on the aquarium may allow you to witness this. Such is its commitment to camouflage it does not usually struggle even when netted or handled, although it does have the ability to emit a grunting sound when removed from the water.

An interesting fact about Chaca species is that they appear to lower the pH of the aquarium water when kept in confined conditions. There is some debate as to the reasons for this; it may be that the fish have particularly potent digestive juices in order to efficiently digest large prey items, or that they use some kind of chemical to assist in luring prey. Another theory is that, due to their inabilty to swim away quickly, they release an acid-containing secretion that makes them taste bad to potential predators. Whichever of these theories is correct, what remains true is that stringent attention to water quality must be paid in aquaria containing Chaca. This is particularly true in smaller volumes of water, in which the chemistry can change more rapidly.