Colossoma macropomum

3) * Colossoma macropomum (Cuvier, 1816);

Serrasalmidae. Blackfin Pacu, Cachama; Colosomo, Cachama Negra, Tambaquí, Pacú (Figs. 2D–E).

Diagnosis: This exotic species can be easily identified from the species of the order occurring in the freshwaters of the country by the presence of rays in the adipose fin (vs. no rays in the adipose fin in the other Characiformes), body shape (robust and oval, with the predorsal profile strongly rounded to concave), color (usually coppery gold in the upper half, dark black in the lower and posterior half and pinkish or reddish in the lower and anterior half) and size (reaching about 1 m total length).

Basis of the record: Several captures have been recently (2017–2021) reported by artisanal and sport anglers in the lower and middle portions (1– 40 m.a.s.l.) of the Tempisque and Bebedero rivers in the north Pacific region of the country. Additional verified records came from the San Carlos River in the north (Atlantic) region of the country.

Remarks: This species was introduced by government agencies and private entities in an attempt to strengthen aquaculture activities and to control the populations of the invasive apple snail (Pomacea sp.). This species is also used in the aquarium trade.