See text Thayeria is a genus of tetras from the Amazon Basin, and the Approuague and Maroni Rivers in tropical South America.

Members of this genus, among other characteristics, are small, have one lateral black stripe, and have a vesica piscis shape.

They like most tetras and family of Characidae thrive in small shoals of 5 individuals or more.

Penguin tetras are commonly found in fish stores and are available from online retailers, they require at least 20 US gallons of swimming area, and will typically grow to around 3 inches.

[1] Thayeria inhabits small streams and the margins of smaller rivers in the lowland Amazon basin, where it is part of the highly diverse Neotropical fish fauna.