''Paedocypris carbunculus'' is a tiny

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

cyprinid Cyprinidae is a family of freshwater fish commonly called the carp or minnow family. It includes the carps, the true minnows, and relatives like the barbs and barbels. Cyprinidae is the largest and most diverse fish family and the largest verte ...

fish

endemic Endemism is the state of a species being found 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 found elsew ...

peat swamp Peat swamp forests are tropical moist forests where waterlogged soil prevents dead leaves and wood from fully decomposing. Over time, this creates a thick layer of acidic peat. Large areas of these forests are being logged at high rates. Peat ...

s and blackwater streams in

Central Kalimantan Central Kalimantan ( id, Kalimantan Tengah) is a province of Indonesia. It is one of five provinces in Kalimantan, the Indonesian part of Borneo. Its provincial capital is Palangka Raya and in 2010 its population was over 2.2 million, while the 2 ...

Borneo Borneo (; id, Kalimantan) is the third-largest island in the world and the largest in Asia. At the geographic centre of Maritime Southeast Asia, in relation to major Indonesian islands, it is located north of Java, west of Sulawesi, and eas ...

, Indonesia. It is the most recently described species of the three in the

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

Paedocypris ''Paedocypris'' is a genus of tiny cyprinid fish found in swamps and streams on the Southeast Asian islands of Borneo, Sumatra and Bintan. ''Paedocypris progenetica'' has been claimed to be the one of smallest known species of fish in the world ...

'' and it reaches up to in

standard length Fish measurement is the measuring of individual fish and various parts of their anatomies. These data are used in many areas of ichthyology, including taxonomy and fisheries biology. Overall length * Standard length (SL) is the length of a fish m ...

. This

shoaling In biology, any group of fish that stay together for social reasons are shoaling, and if the group is swimming in the same direction in a coordinated manner, they are schooling. In common usage, the terms are sometimes used rather loosely. Ab ...

species has been kept and bred for several generations in

aquarium An aquarium (plural: ''aquariums'' or ''aquaria'') is a vivarium of any size having at least one transparent side in which aquatic plants or animals are kept and displayed. Fishkeepers use aquaria to keep fish, invertebrates, amphibians, aq ...

s. The male ''Paedocypris carbunculus'' has a unique pelvic fin, along with a keratinized pad, that allows the male to latch on to the female for sexual reproduction.Kottelat, M., Britz, R., Hui Tan, H., Witte, K. (2006). Paedocypris, a new genus of Southeast Asian cyprinid fish with a remarkable sexual dimorphism, comprises the world's smallest vertebrate. Proc. R. Soc. B.273895–899.

References

Paedocypris Cyprinid fish of Asia Freshwater fish of Indonesia Taxa named by Maurice Kottelat Endemic fauna of Borneo Endemic fauna of Indonesia Fish described in 2008 {{Cyprinidae-stub