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

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 ...

of tropical freshwater fish belonging to the family

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

. It is native to South America. The fish is named in honor of German aquarist

Johann Paul Arnold Johann, typically a male given name, is the German form of ''Iohannes'', which is the Latin form of the Greek name ''Iōánnēs'' (), itself derived from Hebrew name ''Yochanan'' () in turn from its extended form (), meaning "Yahweh is Gracious" ...

(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 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 ...

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: ''nanos'' = small, and the Latin: ''stomus'' = relating to the mouth), is a genus of fish belonging to the characin family Lebiasinidae. All of the species in this genus are known as pencil fish or pencilfish, a ...

es (''Nannostomus''). The

maxilla The maxilla (plural: ''maxillae'' ) in vertebrates 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 t ...

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 located on the back of most marine and freshwater vertebrates within various taxa of the animal kingdom. Many species of animals possessing dorsal fins are not particularly closely related to each other, though through conv ...

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 epithelial ...

and no

adipose fin Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as s ...

Distribution and habitat

The species is

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 ...

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 , with 76.3 percent of it in Venezuela and the remainder in Colombia. It is the fourth largest river in the wor ...

to the

Amazon River The Amazon River (, ; es, Río Amazonas, pt, Rio Amazonas) in South America is the largest river by discharge volume of water in the world, and the disputed longest river system in the world in comparison to the Nile. The headwaters of t ...

. It is found in shallow streams, both in

clearwater Clearwater or Clear Water may refer to: Places Canada * Clear Water Academy, a private Catholic school located in Calgary, Alberta * Clearwater (provincial electoral district), a former provincial electoral district in Alberta * Clearwater, Briti ...

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 meal 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 by coati ...

fall into the water below.

References

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