Bronze Corydoras

• It breathes air: it comes to the surface, gulps a bubble and absorbs it in the gut, which lets it survive in pools with almost no oxygen.
• The spines of its pectoral and dorsal fins lock in the erect position and can stick into a predator's mouth or into the hands of anyone handling it.
• Fertilisation is peculiar: the female drinks the male's sperm, passes it through her gut and releases it over the eggs she holds between her pelvic fins.
• It breathes air through its gut. It rises to the surface, gulps a mouthful and absorbs the oxygen through the intestinal wall, expelling the surplus through the anus. It does so between one and forty-five times an hour, depending on the oxygen in the water.
• That accessory breathing is what lets it live in shallow, poorly oxygenated pools where other fish cannot cope.
• It lives in shoals of twenty to thirty individuals and becomes stressed if kept alone.
• It has a sharp spine on its pectoral, dorsal and anal fins, with a mild toxin that makes fish that try to swallow it let go.
• During breeding it adopts the so-called T-position: the male places himself perpendicular to the female, who collects the sperm with her mouth and then deposits the eggs, a millimetre across, stuck to the substrate.
• It has been established as an introduced species on two islands of Hawaii since the 1980s.

Skeleton type

Vertebrate - internal bony skeleton (fish)

Habitat & environment

Streams, pools and soft-bottomed backwaters of South America

Sources consulted: https://es.wikipedia.org/wiki/Corydoras_aeneus