The Carinotetraodon Genus

Carinotetraodon is a genus of true freshwater pufferfish (Tetraodontidae) endemic to South and Southeast Asia. These small, intelligent fish are collectively known as the Asian dwarf puffers, and they include some of the smallest puffer species on Earth, typically ranging from 2.5 to 4.5 cm in total length, and inhabit lowland rivers, forest streams, and floodplain habitats across South and Southeast Asia.

Historically, Carinotetraodon was part of the great “wastebasket” of Tetraodon, a broad, catch-all genus that for decades encompassed both African and Asian species. This ambiguity persisted well into the twentieth century, with many dwarf puffers still listed under Tetraodon despite clear differences in anatomy and ecology.

Modern revision began in the 1990s as ichthyologists re-examined Asian puffers using improved morphological and molecular methods. These studies demonstrated that Tetraodon was polyphyletic and required major reclassification.

By the early 2010s, the Asian freshwater puffers had been divided into three well-defined genera:

• Carinotetraodon – small, fully freshwater “dwarf puffers” of South and Southeast Asia

• Pao – larger riverine puffers of mainland Southeast Asia

• Dichotomyctere – brackish and coastal species of South and Southeast Asia

The Year the Puffers Split: Unpacking the 2013 Taxonomic Revolution

Carinotetraodon species inhabit calm, vegetated waters such as forest creeks, floodplain pools, and peat-stained rivers. They are active, inquisitive micropredators feeding on small snails, insect larvae, worms, and crustaceans. Despite their miniature size, they exhibit the same alertness, problem-solving ability, and territorial nature seen in larger puffers. Males often display vivid red eyes, darkened bodies, and bright caudal fins during courtship or dominance displays.

In aquaria, they are renowned for their intelligence and charm but require careful stocking and attention to water quality. Their behaviour and adaptability have made them popular subjects for freshwater specialists around the world.

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Recognised Species within the Carinotetraodon genus:

• Carinotetraodon travancoricus – Pea Puffer / Dwarf Puffer The smallest pufferfish in the world, reaching only 2.5 cm. Endemic to India’s Western Ghats, confirmed from Kerala and into southern Karnataka, where it inhabits slow-flowing, plant-choked streams. Hugely popular in aquaria, but still demanding in terms of diet and environmental stability. Best kept in species-only setups due to its territorial nature. Click here to read our care guide

• Carinotetraodon irrubesco – Red-Tailed Red-Eye Puffer

  A small but vividly marked species from Sumatra and Borneo. Males develop a bright red tail and red eyes, making them one of the most attractive of the dwarf puffers. They require heavily planted aquaria with numerous hiding places to reduce aggression. Click here to read our care guide
  

• Carinotetraodon imitator – Imitator Puffer

  Closely related to the pea puffer and also native to Kerala, India. It reaches a similar size (around 2.5–3 cm) but differs in patterning, with less distinct spotting and subtler markings. Rarely encountered in the aquarium trade and often misidentified as C. travancoricus. There is no dedicated guide for this species, but its requirements are identical to those of C. travancoricus, so keepers are advised to refer to the Pea Puffer guide for correct care.
  

• Carinotetraodon lorteti – Red-Eye Puffer

  Widespread in Southeast Asia, particularly in Thailand and Cambodia. Males are easily recognised by their vivid red eyes and darker colouration, while females are more plainly marked. Known for being aggressive and best kept in pairs or singly.
  

• Carinotetraodon borneensis – Bornean Red-Eye Puffer Found in the island’s forest streams, this species closely resembles C. lorteti but is more restricted in range. It remains small, with males showing red eyes and stronger markings than females. Rare in the aquarium trade.
  

• Carinotetraodon salivator – Striped Red-Eye Puffer Native to Borneo and Sarawak. Distinguished by vertical striping along the body. Another small, aggressive species requiring dense planting and careful stocking.