Carinotetraodon irrubesco

Lore & Background

Carinotetraodon irrubesco grows to around 44 mm (1.7 in). Sexual dimorphism is apparent: males are larger and colored brown with creamy stripes on the flanks and dorsal surface, while females are smaller and mottled brown with irregular markings on the ventral surface. Both sexes have red eyes, but only males possess a red caudal fin. The species lives in murky, acidic water amongst submerged vegetation alongside rasboras, pipefish, halfbeaks, and gobies. In the wild, it uses abundant vegetation to hide from predators and also wallows and buries itself in soft substrate for protection.

Reader's Guide

Carinotetraodon irrubesco is found in the aquarium trade and has no other commercial importance. In captivity, it should be kept in a heavily planted tank to make it feel safe and secure, mimicking its natural environment where it uses vegetation to hide from predators. The substrate must be very soft fine sand at least 2 cm (0.79 in) deep, as the fish will wallow and bury itself in the substrate for protection; harder substrates would injure the fish when it attempts to do so. Its natural habitat includes murky, acidic water shared with rasboras, pipefish, halfbeaks, and gobies. The species is restricted to the lower Banyuasin basin in South Sumatra and the Sambas River in West Kalimantan, Indonesia.

Did You Know?

• Only males have a red caudal fin.
• Both sexes have red eyes.
• It is found only in the lower Banyuasin basin and the Sambas River in Indonesia.