''Betta cracens'' is a species of

gourami Gouramis, or gouramies , are a group of fresh water, freshwater Anabantiformes, anabantiform fish that comprise the family (biology), family Osphronemidae. The fish are native to Asia—from the Indian Subcontinent to Southeast Asia and northeas ...

endemic Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...

to the island of

Sumatra Sumatra () is one of the Sunda Islands of western Indonesia. It is the largest island that is fully within Indonesian territory, as well as the list of islands by area, sixth-largest island in the world at 482,286.55 km2 (182,812 mi. ...

Indonesia Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania, between the Indian Ocean, Indian and Pacific Ocean, Pacific oceans. Comprising over List of islands of Indonesia, 17,000 islands, including Sumatra, ...

. It is an inhabitant of freshwater swamp forest. This species grows to a length of , typically inhabits blackwaters that have very soft and very acidic water and is a

bubble nest Bubble nests, also called foam nests, are created by some fish and frog species as floating masses of bubbles blown with an oral secretion, saliva bubbles, and occasionally aquatic plants. Fish that build and guard bubble nests are known as aph ...

brooder. The Latin term ''cracens'' means "slender" or "elegant" and is so named because of the fish's slender body. It was first described in 1996 by

Heok Hui Tan Heok Hui Tan is a Singaporean ichthyologist at the Lee Kong Chian Natural History Museum of the National University of Singapore. Dr. Tan's main interest lies in the systematics of Southeast Asian freshwater fishes, encompassing taxonomy, ecol ...

and Peter K. L. Ng in ''

The Raffles Bulletin of Zoology ''The Raffles Bulletin of Zoology'' is a peer-reviewed open-access scientific journal published by the Lee Kong Chian Natural History Museum at the National University of Singapore. Overview It covers the taxonomy, ecology, and conservation of S ...

''. The ''Betta Cracens'' have a Labyrinth Organ, a morpho-physiological adaptation that allows them to respirate in air. The Labyrinth Organ is a folded suprabranchial accessory breathing organ and a defining characteristic of fish in the suborder

Anabantoidei The Anabantoidei are a suborder of Anabantiformes, anabantiform ray-finned fish, ray-finned freshwater fish distinguished by their possession of a lung-like labyrinth organ, which enables them to breathe air. The fish in the Anabantoidei suborder ...

. It is formed by vascularized expansion of the epibranchial bone of the first gill arch. This adaptation allows these fish to thrive in their harsh habitats.

References

cracens Taxa named by Heok Hui Tan Taxa named by Peter Kee Lin Ng Fish described in 1996 {{Anabantiformes-stub