''Copella arnoldi'', commonly known as the splash tetra or the splashing tetra, is a

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

of tropical freshwater fish belonging to the family

Lebiasinidae The Lebiasinidae are a family (biology), family of freshwater fishes found in Costa Rica, Panama, and South America. They are usually small and are known as ornamental fishes in Aquarium, aquaria, including popular fishes such as the various penc ...

. It is native to South America, and has been introduced to the island of Trinidad. The fish is named in honor of German aquarist Johann Paul Arnold (1869–1952), who collected the type specimen.

Description

The splash tetra is a small, slender fish with a

standard length Fish measurement is the measuring of individual fish and various parts of fish anatomy, their anatomies, for data used in many areas of ichthyology, including Taxonomy (biology), taxonomy and fishery biology. Overall length Standard length (SL) is ...

of . The mouth is relatively large and upturned, with acutely pointed teeth; this contrasts with the more horizontal mouth of the rather similar

pencil fish ''Nannostomus'' (from the Greek language, Greek ''nanos'' = small, and the Latin ''stomus'' = relating to the mouth) is a genus of fish belonging to the Characiformes, characin family (biology), family Lebiasinidae. All of the species in this gen ...

es (''Nannostomus''). The

maxilla In vertebrates, the maxilla (: maxillae ) is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. The two maxil ...

ry bones are curved in an S-shape and the nostrils are separated by a ridge of skin. There is a dark spot on the

dorsal fin A dorsal fin is a fin on the back of most marine and freshwater vertebrates. Dorsal fins have evolved independently several times through convergent evolution adapting to marine environments, so the fins are not all homologous. They are found ...

and a dark line from the snout to the eye, which may continue to the operculum. There is no

lateral line The lateral line, also called the lateral line organ (LLO), is a system of sensory organs found in fish, used to detect movement, vibration, and pressure gradients in the surrounding water. The sensory ability is achieved via modified epithelia ...

and no

adipose fin Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish swim. Apart from the tail or caudal fin, fish fins have no direct connection with the back bone and are supported only b ...

Distribution and habitat

The species is

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 tropical river basins in South America where it is present in river systems from the

Orinoco The Orinoco () is one of the longest rivers in South America at . Its drainage basin, sometimes known as the Orinoquia, covers approximately 1 million km2, with 65% of it in Venezuela and 35% in Colombia. It is the List of rivers by discharge, f ...

to the Amazon River. It is found in shallow streams, both in clearwater forest creeks and in blackwater creeks in swamps and wetlands.

Ecology

Worms, crustaceans and other invertebrates, particularly small insects that fall onto the surface of the water, make up the splash tetra's diet. This fish has an unusual system of reproduction, with the male fish caring for the eggs. During the breeding season, the male chooses a suitable location with overhanging foliage. When he has attracted a female to this spot, the pair simultaneously leap out of the water and cling onto a low-hanging leaf with their pelvic fins for up to ten seconds. Here the female lays a batch of six to ten eggs which are immediately fertilised by the male, before both fish fall back into the water. Further batches are laid in a similar manner until there are 100 to 200 eggs on the leaf and the female is spent. The male remains close at hand, repeatedly splashing water onto the eggs to keep them damp. The rate of splashing is up to about 38 splashes per hour. The eggs hatch after some 36 to 72 hours and the

fish fry A fish fry is a social event containing battered or breaded fried fish. It usually also includes french fries, coleslaw, macaroni salad, lemon slices, tartar sauce, hot sauce, malt vinegar and dessert. Some Native American versions are cooked ...

fall into the water below.

References

{{Taxonbar, from=Q841996 Lebiasinidae Tetras of Brazil Fish of French Guiana Fish of Guyana Fish of Suriname Fish described in 1912 Taxa named by Charles Tate Regan