abramis can develop reversible dermal extensions, possibly as a way to increase the efficacy of aquatic surface respiration (ASR). Previous research on similar traits had revealed a demonstrable link between morphological plasticity and ASR, and this is likely to remain the case in A. abramis. ASR is a trait in many species of fish that need to cope with hypoxic environments. Astyanax abramis lives in syntopy with sister species A. lacustris. It is also known to live in sympatry with other congeners, including A. puka, A. asuncionensis, A. eigenmanniorum, and A. lineatus, specifically in the Juramento River. Because it is an unspecialized feeder that also eats other fish, sympatry with smaller species is unlikely. Astyanax abramis is also subject to parasite infestation. The parasitic nematode worm Procamallanus (Spirocamallanus) hilarii has been recorded from a wide variety of neotropical fish species, including A. abramis. Reproduction Astyanax abramis has a split spawning season, with higher reproduction activity in April and October. These months correspond with periods of higher water temperature and greater rainfall. In female fish, the length of the body is positively correlated with the size of the ovaries, so a period of greater reproductive activity is likely to have more large female specimens. Diet Astyanax abramis is a highly-adaptable omnivore that lives in regions strongly influenced by flood cycles. The intestines can become larger in periods of food scarcity, which allows it to eat items that are more difficult for it to digest, like plant material. Juveniles, being smaller, are not afforded as much flexibility, and as such are sometimes more carnivorous than the omnivorous adults. Other studies report that the juveniles are more herbivorous than the adults, but this is likely explained by environmental differences; there is also evidence that general food abundance influences diet (such as increased allochthonous plant consumption in areas with plentiful riparian vegetation), which means that the role of A. abramis in the trophic system changes depending on the region. Disregarding age, however, smaller adults also tend to be more carnivorous than larger adults, further diversifying observed feeding habits. Conservation status Astyanax abramis has not been evaluated by the IUCN. Given its wide distribution and the fact that it can easily be collected in various locations, it is most likely to be a species of least concern. For instance, in an evaluation of the fish fauna of the Yabotí stream, Hirt et al. ranked A.