Leptobarbus rubripinna

Leptobarbus: from the Ancient Greek λεπτός (leptós), meaning 'thin/slender', and the generic name Barbus, within which the type species, L. hoevenii, was originally placed.

rubripinna: from the Latin ruber, meaning 'red', and pinna, meaning 'fin', in reference to the red fins in this species.

Widely-distributed in the middle and lower Mekong River system in Laos, Thailand, Cambodia, and Vietnam, plus the Chao Phraya and Mae Klong watersheds in central and western Thailand.

Type locality is 'Kemarat, Mekong drainage, Thailand'.

A pelagic species primarily inhabiting rivers and larger streams but also some man-made lakes such as Bueng Boraphet reservoir in central-western Thailand. Adults tend to be found in deeper areas such as pools or slow-moving stretches, but sometimes move into faster-flowing water to feed.

During the rainy season it is known to migrate into temporarily-inundated floodplains and forests, where spawning takes place.

Suitable only for public installations or the very largest private aquaria.

Choice of décor is not as critical as water quality and the amount of open swimming-space provided. However should you possess the means to both provide and decorate a sufficiently-sized aquarium this species a set-up designed to resemble a flowing river with a substrate of variably-sized rocks and gravel, some large water-worn boulders and driftwood branches is recommended.

Like many fishes that naturally inhabit running waters it is intolerant to the accumulation of organic wastes and requires spotless water at all times in order to thrive. It also does best if there is a high level of dissolved oxygen and a decent level of water movement in the tank so external filters, powerheads, etc., should be employed in order to obtain the desired effect.

Be sure to fit the aquarium with a heavy, tightly-fitting cover as larger cyprinids can be quite skittish at times and usually possess a powerful jump.

Stomach analyses of wild specimens have shown it to feed on plant matter, zooplankton and larger invertebrates both aquatic and terrestrial.

In the aquarium it is easily-fed and will accept just about anything offered. For it to develop its best colours and condition offer regular meals of small live and frozen foods such as chironomid larvae (bloodworm), Daphnia and Artemia along with good quality dried foods and plenty of vegetable matter. Shelled peas, blanched courgette, spinach and chopped fruit all make good additions to the menu, while larger specimens will also take chopped earthworm, prawn, mussel, etc.

Peaceful although very small fishes are likely to be eaten.

Sexually mature females are deeper-bodied than males.

Has not been bred in aquaria to date but is cultivated in large numbers in Thailand via the use of hormones.

This species was referred to as its congener Leptobarbus hoevenii for a number of decades and continues to be misidentified as such in the aquarium hobby, with both species traded under the same name.

It is a popular sport fish in its native countries and is wholly unsuitable for private aquaria. Unfortunately it is readily available at a size of 100 – 150 mm3.9 – 6 in, generally with no indication as to its adult size or long term requirements.

Both L. rubripinna and L. hoevenii are also referred to by the names 'mad barb', 'sultan fish', 'maroon shark' or 'Hoven's carp'. The first is particularly interesting because it refers to a phenomenon whereby the fish reportedly consume seeds and other parts of the Chaulmoogra tree (Hydnocarpus kurzii) and subsequently appear to be 'intoxicated', losing orientation and swimming erratically. Across some parts of its range it can therefore be poisonous to eat at certain times of the year.

L. rubripinna can be distinguished from L. hoevenii by: presence (vs. absence) of a broad, dark midlateral stripe on the body; interorbital area rounded (vs. almost flat) in specimens measuring at least to 160 mm6 in SL; dorsal head profile slightly rounded and symmetric with ventral profile (vs. straight to slightly concave); eye located at mid-depth of head (vs. located closer to dorsal surface); posterior maxillary barbel reaching middle of eye (vs. extending beyond eye); pelvic and anal fins orange to red (vs. dark grey); anal-fin and caudal-fin lobes rounded (vs. pointed).