Chameleon fish

The chameleon fish earned its name from its remarkable ability to shift colour in seconds — from deep maroon and rusty orange to pale beige — depending on mood, breeding condition, and social rank. Native to the Ganges basin from Himachal Pradesh through West Bengal and into Bangladesh, this small micropredator inhabits shallow, slow-moving water among leaf litter and submerged roots. Males reach about 6 cm standard length and are territorial toward conspecifics but peaceful with other small fish, making them suitable for a calm community tank of at least 72 litres with plenty of cover. Unlike many aquarium fish, Badis badis prefers cooler conditions: 15–25°C with a pH of 6.0–7.5, which means it can be kept without a heater in most indoor rooms. It is a micropredator and will often refuse dried flake; live or frozen daphnia, mosquito larvae, and brine shrimp are accepted readily. A cave-forming setup with half-coconut shells or upturned clay pots suits its breeding habit: the male guards a clutch of 30–100 eggs deposited on the cave ceiling, with fry becoming free-swimming after 6–8 days. Keep one male with two or three females in a species-only tank for best results, or pair it with small danios or rasboras that stay near the surface.