Tetraodon nigroviridis

Tetraodon nigroviridis is one of the pufferfish known as the green spotted puffer. It is found across South and Southeast Asia in coastal freshwater and brackish water habitats. Tetraodon nigroviridis reaches a maximum length of about 15 cm (5.9 in). In February 2009 it was successfully bred in captivity at University of Florida using a new variation of the ovarian lavage technique.

Ecology
Adult Tetraodon nigroviridis are found in freshwater streams, rivers, and flood plains; young are found in brackish water. It is also found in mangrove forests. This is however disputed and the exact habitat of this fish is not yet fully known. Diet consists primarily of snails, but includes small invertebrates such as mollusks, crustaceans, and some plant material. This species may also be lepidophagous.

Genetics
Tetraodon nigroviridis has the smallest known vertebrate genome, roughly 340 million base pairs, and has thus been selected as a model organism for genetics. In 2004 a draft of its genome sequence was published.

Commercial importance
Tetraodon nigroviridis is by no means a food fish, but has some value as bait and is very widely traded as an aquarium fish, and is sometimes mistaken as the Ceylon Puffer, or Tetraodon fluviatilis. Tetraodon nigroviridis also has some degree of value as a lab animal, in particular in the field of genetics, because it has the same number of genes as human beings but in a genome about one-tenth the size.