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Tigerfish, Coius or Datnioides spp.
Tigerfish are a small family of peripheral freshwater fish restricted to Southeast Asia from India to New Guinea. They resemble snappers in basic shape, with a laterally compressed body, large eyes, and a very big mouth. The soft parts of the dorsal and anal fins project backwards and are positioned close to tail fin, resulting in a distinctive configuration that has given them the common name ‘tripletail’ among ichthyologists, the name ‘tigerfish’ being more widely used among aquarists and fishermen.
In terms of ecology tigerfish are all solitary stealth hunters. They prefer to hide among plants waiting for prey to swim into range. The light and dark stripes on the flanks and the pale stripe down the forehead all serve to break up the outline of the fish, making it more difficult for its prey to spot.
Tigerfish have a preference for large, well-planted tanks with lots of hiding places. In freshwater or slightly brackish conditions, plants such as giant Vallisneria and robust Sagittaria can be used to provide precisely the environment they like. Alternatively plastic plants can be used, and this may be preferred in tanks where the salinity is too high for freshwater plants to do well.
Tigerfish are territorial but otherwise peaceful predatory fish that mix well with other types of fish that are too large to be eaten. Scats, monos, ariid catfish and archerfish all make excellent companions, provided such tankmates are at least equal in size to the tigerfish. Some species will tolerate other tigerfish (either their own kind or other species) but others are much more aggressive.
All the tigerfish are predatory and prefer live foods. In the wild they are reported to feed on crabs, prawns, fish and insect larvae. In the aquarium they are very adaptable and happily take river shrimps and earthworms; once settled they will also accept frozen fish, chopped seafood, and sometimes even pellets. They quickly become tame, and can make extremely good pets.
Five species are currently recognised, of which three are primarily freshwater fish in the wild, while two are found in both fresh and brackish waters. In captivity all species have been found to be extremely adaptable, and the freshwater species do perfectly well in low salinity environments. Conversely, the brackish water species appear to be able to live long and happy lives in hard, basic freshwater aquaria.
Freshwater species (freshwater to SG 1.005)
- Datnioides microlepis
- Datnioides pulcher
- Datnioides undecimradiatus
Fresh and brackish water species (freshwater to SG 1.010)
- Datnioides campbelli
- Datnioides polota (= D. quadrifasciatus)
Commonly Traded Species
- Common or Four-stripe Siamese Tigerfish, Datnioides polota
- One of the most frequently seen species is the Siamese tiger fish Datnoides polota (= D. quadrifasciatus), a species naturally found in estuaries and able to do equally well in either hard freshwater or brackish water conditions (up to SG 1.010). It is a very attractive species when young, being silvery white and bearing one thick black stripe running vertically through the eye, four more on the flanks, and then at least a couple more along the tail between the dorsal fin and the caudal fin. As the fish matures the contrast between the stripes and the background colour lessens while the fish takes on a more brassy or brownish hue. It generally tolerates conspecifics well and makes a good community tank fish.
- Finescale or Three-stripe Siamese Tigerfish, Datnioides microlepis
- A second species of tiger fish widely offered for sale is the finescale or three-stripe tiger fish Datnoides microlepis. It is outwardly very similar to the Siamese tiger fish, though as the common name suggests some specimens have three stripes on the flanks instead of four. Although tolerant of slightly brackish water SG 1.005 or less, it is a strictly freshwater fish in the wild. Social behaviour is similar to D. polota.
- New Guinea Tigerfish, Datnioides campbelli
- Datnoides campbelli is a truly euryhaline species that in the wild migrates freely between fresh and brackish water in search of food. It is best kept at a specific gravity of 1.005 to 1.010 depending on the needs of its tankmates. Compared with the other Datnoides it has a warmer, more mottled background colour against which the stripes are set, and the head region is more or less completely dark. Datnoides campbelli has a mixed reputation as far as sociability goes, with some aquarists considering it to be rather aggressive compared with the other tiger fish.