Orangefin tetra

The orangefin tetra (Bryconops affinis)[1][2] is a small species of freshwater fish from South America that belongs to the family Iguanodectidae.

The orangefin tetra is relatively small, reaching a maximum of 12.0 cm (4.7 in) in total length;[3] this makes it similar in size to its congeners B. caudomaculatus and B.

[4] The body shape is generally reminiscent of all Bryconops species, described as "smelt-like", similar to the genus Piabucus.

[6] The common name "orangefin tetra" originates from the spots of bright orange on the caudal fin on both the upper and lower lobes.

[12] The former name, however, still holds some accuracy; Creatochanes technically stands as a subgenus of Bryconops, to which B. affinis belongs (alongside B. caudomaculatus and B.

[14] However, research from Oliveira et al. in 2011 prompted Bryconops, along with Piabucus and Iguanodectes, to be moved to the family Iguanodectidae, which was revived from the work of ichthyologist Carl H.

[20] Ichthyologist John D. Haseman attributed B. affinis' wide distribution to the fact that it has a more generalist nature than its congeners.

[30][31] The zona pediculla, one of the outer layers of the egg, displays structural specializations during formation that likely play a role.

This is a vintage photograph of five fish. The first in line is somewhat football-shaped and has a dark spot on its dorsal fin. The second is shaped similarly to the first, but has a dark spot on its tail fin. The third is more elongate than the first two, and has a dusky tail fin. The fourth is similar in shape to the third, and has a dark stripe on its tail fin that veers upwards from the center. The fifth is similar in shape to the fourth and third, and has a distinct bright spot on the upper lobe of its tail fin.
Bryconops affinis is the center fish in this photograph. At the time, it was called Creatochanes affinis .