Eirmotus octozona

Overview

Eight dark body bars characterize Eirmotus octozona, a small shoaling fish needing quiet companions and tiny food. It shares the false eight-banded barb trade name with Eirmotus insignis, so dorsal markings and other details deserve attention when buying.

Distribution & habitat

Traceable commercial collections come from Johor on the Malay Peninsula. The aquarium specimens used for the original description were supposedly from Thailand's Bueng Boraphet, but subsequent extensive sampling did not find it there. Any Thai occurrence may be confined to the southern peninsula.

Collectors have mentioned peat-swamp forest near Ayer Hitam, Johor. Extensive habitat disturbance prevents assuming that historical sites still support intact populations. Bornean reports probably concern a similar species. Its precise habitat is unconfirmed; the different stream, swamp, and lake-margin environments occupied by relatives cannot all be assigned to it.

Aquarium setup

A densely planted aquarium or dim forest-stream layout is appropriate. Use a soft bottom, roots, branches, and leaves with tolerant ferns, mosses, or Cryptocoryne. Keep filtration gentle rather than producing strong current.

Imported members of the genus often arrive in poor condition and appear sensitive to changing water chemistry. Use a mature stable aquarium and regular changes of about 10% to limit abrupt shifts.

Diet & feeding

Small invertebrates, algae, and zooplankton are possible natural foods. Suitable dry preparations are accepted, but daily tiny live or frozen water fleas, Artemia, and similar offerings remain useful.

New imports may be weak and hesitant. Begin with small live prey, adding frozen and dry foods after they settle. Check that competitors are not taking the food first.

Behaviour & compatibility

Large, boisterous, or forceful feeders make an ordinary community unsuitable. Small peaceful cyprinids are better companions. Small characins or bottom catfishes may also work, but those possibilities still need observation.

At least eight to ten individuals reduce nervousness and promote natural group behavior. Males competing for female attention display stronger color and more conspicuous interactions.

Sexual dimorphism

Adult males are distinctly slimmer. In good condition their unpaired fins develop a pale reddish tint.

Breeding

No established aquarium breeding method is available.

Notes

The eight bars extend from the snout to the tail base. A large clear black mark before the anus is visible from the side and below. Unbranched dorsal rays are dark, sometimes including the first branched ray, while most remaining fin tissue is clear. These features distinguish similar fish more effectively than simply counting bars.

The genus has head sensory papillae, an incomplete lateral line, and no barbels. Its long history as a single recognized species ended with the 2008 revision, so old trade names should not be treated as precise identifications.