Flounder

Nostril diameter 1.5-2 times orbital diameter; color pattern consisting of a light brown background with irregular, scattered dark brown blotches, the largest ones 2-7 times interorbital space; caudal fin pointed (median rays proportionally longer than external ones); presence of gill openings on both eyed sides; absence of scales on the interorbital space (Ref. 49504).

Amphidromous. Refers to fishes that regularly migrate between freshwater and the sea (in both directions), but not for the purpose of breeding, as in anadromous and catadromous species. Sub-division of diadromous. Migrations should be cyclical and predictable and cover more than 100 km.Characteristic elements in amphidromy are: reproduction in fresh water, passage to sea by newly hatched larvae, a period of feeding and growing at sea usually a few months long, return to fresh water of well-grown juveniles, a further period of feeding and growing in fresh water, followed by reproduction there (Ref. 82692).

Dorsal spines (total): 0; Dorsal soft rays (total): 57 - 75; Analspines: 0; Analsoft rays: 40 - 55; Vertebrae: 34 - 38

Rare. Adults occur over sandy-muddy bottoms of the littoral zone and estuaries. Little is known of its biology (Ref. 35237). Maximum length reported to reach 15 cm TL (Ref. 5217).

aquarium: commercial

The longtail sole (Apionichthys dumerili) is a species of sole in the family Achiridae. It was described by Johann Jakob Kaup in 1858. It inhabits the Amazon, Corantijn, Grajaú, Orinoco, and Oyapock rivers. It dwells at a depth range of 1 to 10 m (3.3 to 32.8 ft). It reaches a maximum total length of 15 cm (5.9 in), more commonly reaching a TL of 11 cm (4.3 in).

The longtail sole is currently ranked as Least Concern by the IUCN redlist, due to a lack of known major threats, although it notes that the species is harvested as bycatch in shrimp trawls at an undetermined rate. The longtail sole is also marketed in the aquarium hobby.