The Amazon leaffish (''Monocirrhus polyacanthus''), or South American leaffish, 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 fish belonging to the family Polycentridae. It is found in the

Amazon basin The Amazon basin is the part of South America drained by the Amazon River and its tributary, tributaries. The Amazon drainage basin covers an area of about , or about 35.5 percent of the South American continent. It is located in the countries ...

Bolivia Bolivia, officially the Plurinational State of Bolivia, is a landlocked country located in central South America. The country features diverse geography, including vast Amazonian plains, tropical lowlands, mountains, the Gran Chaco Province, w ...

Brazil Brazil, officially the Federative Republic of Brazil, is the largest country in South America. It is the world's List of countries and dependencies by area, fifth-largest country by area and the List of countries and dependencies by population ...

Colombia Colombia, officially the Republic of Colombia, is a country primarily located in South America with Insular region of Colombia, insular regions in North America. The Colombian mainland is bordered by the Caribbean Sea to the north, Venezuel ...

Peru Peru, officially the Republic of Peru, is a country in western South America. It is bordered in the north by Ecuador and Colombia, in the east by Brazil, in the southeast by Bolivia, in the south by Chile, and in the south and west by the Pac ...

and

Venezuela Venezuela, officially the Bolivarian Republic of Venezuela, is a country on the northern coast of South America, consisting of a continental landmass and many Federal Dependencies of Venezuela, islands and islets in the Caribbean Sea. It com ...

, where it inhabits edges of rivers and lakes, and streams. It is generally a low-density species that lives in slow-moving or essentially stagnant waters in areas with plant debris. Amazon leaffish are sometimes kept in aquariums, but they require acidic water, low light and live prey.

Appearance

The Amazon leaffish reaches a maximum

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 , and a total length of . As suggested by its common name, it closely resembles a dead leaf. The flattened body and filament at the tip of the lower jaw (resembling a stalk) further enhances its similarity to a leaf. It is gray-brown, but can change its color to some extent. 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 its large mouth can be protracted to as much as 60% of the head length.

Behavior

The Amazon leaffish is highly predatory, feeding on small invertebrates (aquatic insects like

mayfly Mayflies (also known as shadflies or fishflies in Canada and the upper Midwestern United States, as Canadian soldiers in the American Great Lakes region, and as up-winged flies in the United Kingdom) are aquatic insects belonging to the orde ...

nymphs A nymph (; ; sometimes spelled nymphe) is a minor female nature deity in ancient Greek folklore. Distinct from other Greek goddesses, nymphs are generally regarded as personifications of nature; they are typically tied to a specific place, land ...

and crustaceans like shrimp) and fish (especially Characids and Lebiasinids). Small

Amazon Amazon most often refers to: * Amazon River, in South America * Amazon rainforest, a rainforest covering most of the Amazon basin * Amazon (company), an American multinational technology company * Amazons, a tribe of female warriors in Greek myth ...

leaffish mostly feed on

invertebrates Invertebrates are animals that neither develop nor retain a vertebral column (commonly known as a ''spine'' or ''backbone''), which evolved from the notochord. It is a paraphyletic grouping including all animals excluding the chordate subphylum ...

, while larger individuals mainly feed on

fish A fish (: fish or fishes) is an aquatic animal, aquatic, Anamniotes, anamniotic, gill-bearing vertebrate animal with swimming fish fin, fins and craniate, a hard skull, but lacking limb (anatomy), limbs with digit (anatomy), digits. Fish can ...

. The prey fish are swallowed whole and they are often quite large compared to the size of the leaffish. The prey fish length is typically about of the length of the leaffish, but can be up to around the length. The

camouflage Camouflage is the use of any combination of materials, coloration, or illumination for concealment, either by making animals or objects hard to see, or by disguising them as something else. Examples include the leopard's spotted coat, the b ...

allows the Amazon leaffish to both escape the attention of larger predators and ambush smaller prey. It swims very slowly in a head-down position, resembling a dead leaf floating in the current, to approach its prey. When near, it protracts its mouth to form a tube. The prey is rapidly sucked in, usually head-first. Prey in its stomach is often folded, allowing the leaffish to fit relatively large items. Before breeding, the pair swims next to each other. The female lays up to 300 eggs on the underside of a rock or plant leaf, which are then fertilized by the male. The male takes care of the eggs, which hatch after 3–4 days. They are predators from the start of their lives, first feeding on tiny animals like

brine shrimp ''Artemia'' is a genus of aquatic crustaceans also known as brine shrimp or ''Sea-Monkeys, sea monkeys''. It is the only genus in the Family (biology), family Artemiidae. The first historical record of the existence of ''Artemia'' dates back to t ...

and

water flea The Diplostraca or Cladocera, commonly known as water fleas, is a superorder of small, mostly freshwater crustaceans, most of which feed on microscopic chunks of organic matter, though some forms are predatory. Over 1000 species have been recog ...

References

{{Taxonbar, from=Q882185 Polycentridae Fish described in 1840 Fish of Bolivia Freshwater fish of Brazil Freshwater fish of Colombia Freshwater fish of Peru Fish of Venezuela