Belodontichthys dinema

Belodontichthys: from the Greek belos, meaning 'arrow', odous, meaning 'tooth', and ichthys, meaning 'fish', in reference to the arrow-shaped jaw teeth of this species.

dinema: from the Greek di-, meaning 'two', and nema, meaning 'thread', in reference to the pair of very thin, short barbels set far back on the chin.

Known from the Malay Peninsula, Sumatra and Borneo, in Malaysia and Indonesia.

In Borneo it's recorded from the Kapuas basin in West Kalimantan, including the lakes of the upper Kapuas (Roberts, 1989; Kottelat and Widjanarti, 2005), and in Sumatra from the central part of the island (Tan and Ng, 2000).

Type locality is 'Bandjarmasin', now Banjarmasin in South Kalimantan, Indonesian Borneo.

Older records from the Mekong and Chao Phraya basins in Thailand, Laos, Cambodia and Vietnam belong to B. truncatus. Kottelat and Ng (1999) described that species from fish previously identified as this one (see 'Notes').[1][2][3][4][5][6]

Inhabits large rivers and their associated lakes, including the seasonally flooded lake system of the upper Kapuas in West Kalimantan (Kottelat and Widjanarti, 2005).

It swims in open water and feeds on smaller fishes.[3]

Needs an aquarium measuring at least 180 ∗ 60 ∗ 60 cm72 ∗ 24 ∗ 24 in, and a fully grown fish needs far more space, since wild specimens reach 100 cm39 in TL.

Give it plenty of open swimming space with a few large hiding places, such as lengths of wide plastic pipe. Few plants will survive the movements of a fish this size.

Filtration should be powerful and efficient, as it's a messy eater that produces a lot of waste, and large, regular water changes are essential.

Keep the tank covered with a heavy, tightly fitting lid, as it's a powerful jumper.

Temperature: 22 – 27 °C72 – 81 °F

pH: 5.6 – 7.0

Hardness: 1 – 10 dGH

An obligate piscivore that feeds on smaller fishes.

Aquarium reports say it takes only live fish, so a keeper needs a steady supply of healthy feeder fish, quarantined before use.

Eats any fish it can fit in its mouth, so it's best kept as a single specimen, or with robust fishes too large to be swallowed.

Males are reported to have a strongly serrated pectoral-fin spine, and mature females are plumper than males.[8]

Not recorded as bred in aquaria, and we have no information on how it breeds in the wild.

Belodontichthys contains two species. B. truncatus Kottelat and Ng, 1999 is the species found in the Mekong and Chao Phraya basins, and it has a shorter head (20.9–23.9% SL, against 24.2–26.0% in B. dinema), a shorter snout (35.4–39.6% of head length, against 39.0–43.1%) and shorter pectoral fins (21.9–25.8% SL, against 25.9–28.9%).

Fish exported from Thailand or elsewhere in Indochina under this name are likely to be B. truncatus.

Bleeker described the species as Wallago dinema in 1851 and renamed it Belodontichthys macrochir in 1858, based on the same type specimens. That second name was unnecessary and is an objective synonym.

FishBase describes a strongly compressed head and body, an upturned snout with the profile concave above the eye, a small dorsal fin with 4 rays, an anal fin with 85–96 rays, and pectoral fins longer than the head.

The IUCN Red List assesses it as Least Concern (2019).[1][5][7]