Mimagoniates

Mimagoniates is a genus of characid fish from rivers and streams in southeastern, southern and central-western Brazil, northeastern Argentina, and Paraguay.[1][2] The individual species generally have relatively small ranges and two, M. lateralis and M. sylvicola, are considered threatened by Brazil's Ministry of the Environment.[3]

Mimagoniates
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Actinopterygii
Order:	Characiformes
Family:	Characidae
Subfamily:	Stevardiinae
Genus:	Mimagoniates Regan, 1907
Synonyms
Coelurichthys Miranda-Ribeiro, 1908

Commonly known as croaking tetra or chirping tetra because they can produce sounds,[4] some of these fish were historically included in Glandulocauda and together with Lophiobrycon they form the tribe Glandulocaudini.[2] Mimagoniates have a supplementary breathing organ located above the gills which makes a faint chirping sound when these fish come to the surface to gulp air. It also plays a role in courtship as the male chases and hovers near the female while taking gulps of air and expelling it to make a rhythmic noise.[4] Croaking behavior may have evolved from a behavior called "surface nipping", which occurs when the fish is searching for food. This gulping of air has no useful respiratory function.[5] They are small fish, up to 3–6.1 cm (1.2–2.4 in) in standard length depending on the exact species.[1]