Eirmotus Octozona

Datasheet

General Description

Prior to a revision in 2008, the genus Eirmotus was monotypic for approximately 50 years, with E. octozona standing as the sole representative until additional species were discovered. There are presently four species within the genus, all sharing a similar appearance. E. octozona can be distinguished from its congeners by specific characteristics such as the presence of a large black mark before the anal fin, distinct dorsal fin coloring, and the number of serrae on its dorsal fin ray. The fish's numbering bars that stretch from the snout to the caudal peduncle have led to the common name 'false eight-banded barb,' also associated with other Eirmotus species available in the ornamental trade. These small fish boast unique sensory papillae rows on their head and a striking red to yellowish body with dark bars.

Aquarium Setup

Eirmotus octozona thrives in heavily planted or forest stream-type aquariums, featuring dim lighting, soft substrate, roots, branches, and leaf litter for decor. Suitable tankmates include peaceful cyprinids like Trigonostigma or Boraras species, small South American characins, Otocinclus, or pygmy Corydoras catfish. It is essential to keep them in groups of at least 8-10 individuals to reduce stress and enhance their natural behavior. Acclimating them to captive environments can be challenging due to their sensitivity to water chemistry changes, so a stable environment with regular water changes is crucial.

Behaviour

Eirmotus octozona is a shoaling fish by nature, displaying more vibrant colors and engaging behaviors when kept in suitable numbers. They are unsuitable for most community tanks as they may get intimidated or outcompeted for food by larger or more aggressive tankmates. Keeping them with compatible species in a biotope-style setup or small groups of their own kind is recommended for their well-being and to observe their natural behavior.

Feeding and Diet

In their natural habitat, E. octozona likely feeds on small invertebrates, algae, and zooplankton. In captivity, they accept dried foods but should also be offered small live and frozen foods like Daphnia and Artemia for optimal coloration and breeding conditions. They may initially be hesitant feeders, especially upon arrival in the aquarium, so starting with live foods and transitioning to dry and frozen options is advised to ensure their health and nutrition.

Reproduction & Dimorphism

As of current knowledge, there is no recorded information on the reproductive habits of E. octozona. Adult males are distinguishable by their slimmer physique compared to females, along with pale red coloration in their unpaired fins when in good health.

Habitat and Distribution

The exact habitat of E. octozona remains unconfirmed, but other members of the genus are known to inhabit shady, slow-moving forest streams, swamps, and peat swamp forests in regions like Peninsular Malaysia. Records suggest that the species might also occur in southern Thailand, specifically in peat swamp forests around Johor state. Despite the species possibly being found in specific locations, disturbances in their habitats have made the current status unclear. Records from Borneo likely refer to a closely related species, E. insignis.