Ocellated Gastromyzon

Gastromyzon ocellatus is distinguished by the presence of one or more prominent ocellated markings — dark spots encircled by a paler ring — on its dorsal surface, a feature that likely serves as predator-deterring mimicry in its native habitat. It inhabits the fast-flowing, boulder-strewn hill streams of Borneo, sharing its range with several other Gastromyzon species. Its scarcity in the trade means that published aquarium experience is limited, but broadly its requirements follow the Gastromyzon template.

In aquaria, G. ocellatus requires the same strong flow, excellent oxygenation, and cool temperature regime as its congeners. New importations should be quarantined for at least four weeks before placement in a display tank. The species may take several weeks to begin feeding confidently on prepared foods, so an established tank with abundant natural biofilm growth is essential for successful acclimatisation.

Long-term care is straightforward for experienced hillstream keepers. The distinctive ocellated markings become more vivid in well-conditioned fish, making healthy specimens noticeably more striking than stressed or underfed individuals.

Water: 22–26°C, pH 6.0–7.0, GH 3–12, KH 1–6; very high oxygenation and consistent strong flow; sensitive to any stagnant water zones in the tank. Tank: 70 L minimum; smooth rounded stones and boulders with established algae and biofilm; no sharp or angular substrate. Feeding: Grazes biofilm; supplement with spirulina wafers, Repashy gel food, and blanched greens after the acclimatisation period. Breeding: No documented captive breeding records at time of writing; treat as per other Gastromyzon species for conditioning attempts. Compatibility: Peaceful; suitable for specialist hillstream biotopes with other cool-water rheophilic species.