Indostomidae - Armored sticklebacks

Indostomus is a genus of small fishes native to slow moving or stagnant freshwater habitats in Indochina. It is the sole genus of the monogeneric family Indostomidae, Long considered to be sticklebacks, within the order Gasterosteiformes, modern analyses place the Indostomids within the order Synbranchiformes, related to the spiny eels and swamp eels.

Indostomus species are all incredibly small, on average reaching 3 cm in length at maximum. Their bodies are armored and thin, tapering towards the back, and ending in a small, fan-shaped tail. They are sexually dimorphic, with mature females outwardly showing the presence of eggs with a broader, fuller abdomen, and, in the case of Indostomus crocodilus, mature males have white bands along the edges of the dorsal, anal, and ventral fins.

Indostomus species show a clear preference for slow moving and stagnant freshwater wetlands, streams, ponds, and oxbow lakes, including both clearwater and blackwater habitats. Indostomus are often found around aquatic plant growth, algae, and decaying organic material such as leaf litter and branches. Sympatric fishes include danionins, Dario, and gouramis.