- Source: Monacoa grimaldii
Monacoa grimaldii, also known as the mirrorbelly, barreleye, Grimaldi's barreleye, and flatiron fish, is a species of fish in the family Opisthoproctidae. Different sources express different views on its distribution. According to Poulsen and colleagues, it is known with certainty only from the Atlantic Ocean, with records from the Pacific Ocean representing other Monacoa species. However, FishBase and Catalog of Fishes include the Pacific, and in the case of the latter, the Indian Ocean in its range. It is typically mesopelagic, but it has been recorded from depths of 0 to 4,750 metres (0 to 15,584 ft). It has a body length of 8 cm (3.1 in) SL.