Zonalternans Loach

Acanthocobitis zonalternans is a striking, mid-sized stream loach characterised by alternating wide and narrow dark bands on a pale body, creating a visually bold pattern that makes it stand out among the subtler Nemacheilidae. It is found in rivers of Southeast Asia in clear, moderately flowing water over sandy and gravelly substrates.

In the aquarium, this species requires clean, well-oxygenated water with moderate current to mimic its natural habitat. Like other Acanthocobitis, it is a social loach and should be kept in groups of five or more, which encourages natural foraging behaviour and reduces timidity. The aquarium should feature fine-grained substrate, flat rocks, and some cave-type hides.

Feeding is straightforward: sinking pellets, frozen bloodworm, and daphnia are accepted eagerly. The Zonalternans Loach is an excellent choice for a Southeast Asian stream biotope alongside danios, hillstream gobies, and other current-loving species. Its bold pattern and active nature make it one of the more rewarding Acanthocobitis species.

Water: pH 6.0–7.5, temperature 20–26°C, well-oxygenated, moderate flow. Tank: 60 L minimum; fine sand, smooth pebbles, flat rock caves. Feeding: Sinking pellets, frozen bloodworm, daphnia, occasional live invertebrates. Breeding: Not documented in captivity. Compatibility: Peaceful; suitable for stream-biotope communities.