Batasio fluviatilis

Overview

A small catfish of the Malay Peninsula, Batasio fluviatilis can be manageable when its stream requirements are met. Clean water, oxygen, and circulation are essential, making an ordinary still-water community an unsuitable default.

Distribution & habitat

Known localities lie south of the Isthmus of Kra in Thailand and Peninsular Malaysia, including the type area in Nakhon Si Thammarat. Typical habitat for the genus is shallow headwater flow over gravel, sand, and rock, with bankside vegetation and patches of leaves but little submerged plant growth.

Aquarium setup

Build a stream-style floor of gravel, varied stones, and worn boulders, with roots and attached plants for cover. Organic pollution is poorly tolerated. Maintain oxygen and water movement with effective filtration and circulation, changing 30–50% each week. Temporary storm turbidity in nature does not justify accumulated waste in captivity.

Diet & feeding

Small aquatic crustaceans, worms, and insect larvae are likely natural foods. Base captive feeding largely on small live or frozen items such as bloodworms, Tubifex, and Artemia. Sinking preparations are sometimes accepted, though newly imported wild fish may initially require other foods.

Behaviour & compatibility

Avoid aggressive or much larger fishes because this catfish is not a strong competitor. Peaceful schooling cyprinids of suitable size are good candidates. Compatible small stream catfish and certain hillstream loaches can share the lower level; assess other loaches by eventual size and territorial behavior.

Sexual dimorphism

Males have a conspicuous elongated genital papilla immediately ahead of the anal fin.

Breeding

Captive breeding has succeeded. Eggs are dispersed without a fixed site and hatch in roughly two days. Once adults are in spawning condition, one or more 50–70% changes using cooler water may act as a stimulus. This is a possible trigger, not a guarantee.