Borneensis Puffer

Carinotetraodon borneensis is the least frequently encountered of the Carinotetraodon species in the aquarium trade and is native to shallow, swampy, often peat-influenced rivers of northern Borneo in Sabah and Sarawak. Its colouration is more subdued than its congeners, with brownish-olive base tones and diffuse spotting. The diminutive adult size makes it suitable for well-planted nano or small aquariums, but water conditions must be carefully maintained at soft, acidic parameters consistent with its blackwater origins. It will not tolerate hard or alkaline water and should never be exposed to untreated tap water with high pH. Stocks are very sporadically available, and it commands significant collector interest when imported.

Water: pH 5.5–7.0, temperature 24–28°C, very soft; conductivity below 150 µS/cm ideal; peat filtration recommended. Tank: 40 L minimum; dense fine-leaf planting, dried leaves, minimal flow; tight lid required. Feeding: Small snails, microworms, frozen daphnia and bloodworm; hard-shelled prey at least twice weekly. Breeding: Not documented in captivity; presumed similar to C. irrubesco. Compatibility: Semi-aggressive; avoid combining with fast or nippy species; single or paired setup best.