Indostomus is a genus of small native to slow moving or stagnant freshwater habitats in Indochina.[
]
Taxonomy
Indostomus was first proposed as a genus in 1929 by the Indian Baini Prashad and Dev Dev Mukerji when they described Indostomus paradoxus,
Description
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.
Habitat
Indostomus species show a clear preference for slow moving and stagnant freshwater wetlands, streams, ponds, and , including both clearwater and Blackwater river habitats. Indostomus are often found around aquatic plant growth, algae, and decaying organic material such as leaf litter and branches. Sympatric fishes include , Dario, and .
Behavior and Diet
Indostomus are micropredatory fish, predating on small aquatic insects, crustaceans, and worms. In an aquarium setting, Indostomus will often refuse prepared foods, only eating very small live or frozen foods such as , Brine shrimp, Daphnia, or Moina.
Indostomus will spawn in very small caves and crevices, such as in reeds, bamboo, or very small lengths of plastic piping. Individual males will select a spawning site, and guard the eggs and nest until the fry are free swimming and disperse.
Species
The three currently recognized species in this genus are:
Indostomus paradoxus, was discovered in the 1920s in Indawgyi Lake in Myanmar. In the 1990s, two other species were discovered and placed into the genus Indostomus.[Britz, R. and M. Kottelat. (1999). Two new species of gasterosteiform fishes of the genus Indostomus (Teleostei: Indostomidae). Ichthyol. Explor. Freshwat. 10(4):327-336.] Indostomus crocodilus from Thailand, and Indostomus spinosus from Mekong basin. In 2001, I. tiliosi was listed as a possible new species, but has not yet been officially described.
Further reading
-
Berra, Tim M. (2001). Freshwater Fish Distribution. San Diego: Academic Press.
