A fishkeeper's guide to Datnioides
Posted by datluckytiger in Tiger Keeper's Guide
A fishkeeper's guide to Datnioides
Sean Evans explains how to keep the stunning Tiger fish of the genus Datnioides.
Copyright © Practical Fishkeeping
The Siamese tigerfish, or Indo-Pacific Tiger perches, enjoy a cult following. They have a very striking appearance with a deep body sporting dark vertical bands. The base colour varies from silvery through various shades of bronze and golden-yellow.
These fish are clearly built to be predators. They have large mouths which can extend to capture prey. They also have large eyes which, rather creepily, move independently and watch your every move.
The tigerfish originate from the fresh and brackish waters of South-east Asia. Of the five species described, three are found almost entirely in freshwater, whereas the other two are largely brackish.
They are not common in aquatic shops, though they can sometimes be found from in specialist stores . They can be expensive, especially for larger specimens of the more sought-after species.
Keeping tigers at home
Do not keep these fish with overly aggressive fish, eg large cichlids. At the other end of the scale, they should not be kept with small fish which they are likely to eat - never under-estimate the size of their extendible mouths! They can usually be kept with non-aggressive fish that are too large to swallow.
Suitable companions include bichirs, knifefish, arowanas, large cyprinids such as Silver sharks and Tinfoil barbs, and medium-sized catfish.
Tigerfish are territorial and semi-aggressive towards their own kind. It is better to keep either a single fish, or a larger group of five or more
of similar size. Just remember that they will need a large tank. Datnioides campbelli is, however, best kept in a tank of its own.
Although relatively slow-growing, all of these species can attain or exceed 30cm/12" in the aquarium, with D. microlepis reportedly capable of reaching 60cm/24" in the wild.
For a single adult specimen, a tank of about 120 x 38 x 38cm/48 x 18 x 18" should be a minimum. To house a group of adults, a 180 x 60 x 60cm/6' x 2' x 2' or larger tank would be more appropriate.
A thin layer of aquarium sand is a suitable substrate and is easy to keep clean. Alternatively, use smooth gravel. Adults should be OK in relatively bare tanks, whereas juveniles will require some cover. If little cover is provided, juveniles in particular are masters at making use of whatever is available. They will lay on their sides in shallow caves or hang vertically behind heaters etc in order to feel secure.
Choose smooth rocks and larger pieces of bogwood for decor. Tall plants are especially suitable, such as Vallisneria and Amazon swords. Or you could always opt for artificial plants as an alternative.
Dim lighting is preferable, though brighter lighting is alright providing there is plenty of plant cover � include some floating plants for shade. Heavily planted tanks will be impractical for adult tigerfish.
Keep these fish at the usual tropical temperature range of 24-28�C/75-82�F. Fairly soft to hardwater, with a pH around neutral or slightly alkaline, is fine for the freshwater species, but hard and alkaline or preferably brackish conditions should be provided for
D. campbelli and quadrifasciatus.
The actual level of salt used is not critical, but a specific gravity of 1.005 (achieved with marine salt) is a good starting point.
Maintain water quality with frequent water changes. High levels of nitrates and other wastes are likely to cause a reluctance to feed and a loss of condition. These fish are intolerant of ammonia and nitrite, so do not add them to uncycled or immature tanks.
These fish are greedy feeders, and the meaty foods they require will pollute the water quickly without adequate filtration.
Strong circulation is not necessary, but good aeration is. These two might seem contradictory, but placing the output from a filter near the surface (or using a spray bar) to cause plenty of surface agitation will increase aeration without introducing a strong current that
the fish have to fight against. An airstone is another option.
Choose filters with plenty of
bio-filtration capacity, such as external canister filters or sump filters.
As for feeding, these fish are predators. They show little interest in dry aquarium foods, though some may take carnivore pellets. Juveniles will accept frozen or live bloodworm and brineshrimp without hesitation. They can also be fed smaller pieces of foods suitable for adults such as cockles, mussels, baitfish � whitebait, lance fish and silversides, prawns or shrimp and earthworms.
Some fish may be initially reluctant to feed, especially those caught from the wild at semi-adult size. It is normal for these fish to take a few days to settle into their new environment first. Foods which wriggle, such as live bloodworm or earthworms, may encourage reluctant fish to start feeding.
Another useful tactic is to place pieces of whitebait or mussel in the outflow of a filter and let this carry the food past the fish. The movement usually encourages the fish to lunge at the food. They may spit it back out initially if it's unfamiliar, but with a little patience, they soon adapt to such foods.
Tigerfish are not prone to specific diseases, and appear to be hardy
fish once settled. There are no clear differences between the sexes and aquarium breeding is unknown. Hopefully this will change as dedicated hobbyists learn more about them.
Species identification
There are five valid species of Datnioides - campbelli, microlepis, pulcher, quadrafasciatus and undecimradiatus. A paper published by Roberts and Kottelat in 1994 discusses campbelli, microlepis and quadrafasciatus, and introduces undecimradiatus as a new species.
Reference is also made to differences in the populations of "microlepis" found in Borneo and Sumatra against those found in the Mekong and Chao Phraya basins, but they are not designated as a separate species or subspecies.
However, in a further paper (Kottelat, 1998), the Mekong and Chao Phraya basin population is designated as a new species, Coius (Datnioides) pulcher, on the basis of a large series of material examined following the 1994 paper. Kottelat states that there are no morphological differences between these two species, but that because they are "diagnosable entities" (primarily on the basis of markings) with separate evolutionary origins, they can be regarded as separate species.
The two largely brackish species, D. campbelli and D. quadrifasciatus, can be relatively easily distinguished. D. campbelli (often known as the New Guinea tigerfish) tends to have a darker head region with dark speckling on the yellowish body, which may show areas of slightly greenish colour. The edges of
the bands are not distinct like
those of the other species.
Some sources seem to have underestimated the maximum potential size of this fish, which seems to be 45cm/18� or larger.
It is rarely encountered in the trade and likely to command a high price. Very recently, there have been a few imports to the UK.
D. quadrifasciatus, sometimes known as the Silver tigerfish, is much more commonly available (at least from more specialist aquatic shops). This species tends to be silver in colour and has a noticeably concave forehead region, or predorsal profile. Partial bars are often present.
This is the smallest of the tigerfish, reaching a maximum of about 30cm/12�. Its natural distribution is much wider than D. campbelli and extends from India to Indonesia and New Guinea.
D. microlepis has often been referred to as the fine-scaled tigerfish. This originally served as a means of distinguishing it from cambelli and quadrifasciatus, which have relatively larger scales. However, the more recently described pulcher and undecimradiatus have similarly fine scales, so this cannot be used as a means of distinguishing between these three.
D. microlepis has also been referred to as being the deepest-bodied of the Datnioides, but this feature was defined when the populations now designated pulcher were regarded as microlepis. Hence body depth is not a clear means of distinguishing between these two. However, both microlepis and pulcher are deeper-bodied than undecimradiatus.
Other clues to identification are based on the pattern of bars on the fishes. In recent times, the colour and markings of different species have been increasingly regarded as significant by ichthyologists. The position of the bands in relation to dorsal spines etc is significant, so a clear photograph of the fish with its fins extended will be very useful.
The exact pattern and number of bars can vary in individual fish, and when examining large numbers of the same species, it becomes apparent that certain individuals may have variant patterns. However, despite this potential variability, the bars can be used in most cases to distinguish between D. microlepis, pulcher and undecimradiatus.
D. undecimradiatus usually has three narrow bars on the body, and so is often referred to as the Thin Bar dat/tigerfish. It comes from the Mekong basin and grows to about 40cm/16� in length.
D. pulcher has the most striking appearance and much wider bands, leading to the common name of Wide Bar dat/tigerfish. Coming from the Mekong and Chao Phraya river basins in Thailand, this should perhaps be considered the original �Siamese� tigerfish. It can grow to about 45cm/18�, but is unlikely to reach this size in aquaria.
D. microlepis comes from Borneo and Sumatra, so is sometimes called the Indonesian tigerfish. The bars are more variable, but there are nearly always more bars present than with D. pulcher. The maximum size quoted varies widely; some say its maximum size is up to 60cm/24�.
Coius, Datnoides or Datnioides?
For many years, the tiger-perches were known as Datnioides. However, in recent years, they were placed in the genus Coius. A number of recent publications and websites have adopted this new genus name.
According to a more recent paper (Kottelat, 2000), it now appears that the correct genus name is Datnioides (Ed�s note: note the spelling � not Datnoides). The paper itself makes for heavy reading if you're not into scientific nomenclature.
The author, Maurice Kottelat,
also states that Datnioididae (not Coiidae) is the valid family-group name for the genus Datnioides.
Ed's note: Since this was published the status of some species has changed. D. quadrifasciatus is now considered a junior synonym, replaced by the name D. polota.
