Black Neon Tetra

The species is named in honor of pet-book publisher Herbert R. Axelrod (1927–2017), whose Tropical Fish Hobbyist magazine published this description and several others by Géry.

Black neon tetras are egg-scattering free spawners, and they show no parental care for fry. The black and white stripes on their sides are used to keep the shoal in contact with each other in turbid water. As black neon tetras are so widely bred, they are no longer collected from the wild for trading. Present in both forest streams and seasonal floodwaters, the black neon tetra is an adaptable species. It prefers acidic habitats with running water and waterlogged debris as well as aquatic plants.

}} Black neon tetras are kept in soft acidic water, although captive-bred they can often survive in mature tap water with a range of 5.5 - 7.5. Black neon tetras are fed a variety of foods, including flake, frozen and freeze dried food, living healthiest on a balanced mix. Contrary to other tetras, black neon tetras tend to shoal discreetly in aquaria.

Black neon tetras can be spawned rather easily if the water quality is right. Before attempting to breed the black neon tetra, breeders condition the prospective parents with live food. Fish around one year old can be suitable for breeding. The sex of the fish is determined by its body shape, the female being much rounder and more plump than the males. Although the black neon tetra can be kept in water harder and more alkaline than its natural habitat, for breeding it is necessary to be closer to what it would feel like in the Amazon. Breeding the Black neon tetra requires acidic water with no more than four degrees of hardness. The black neon tetra is an egg scatterer, laying adhesive (sticky) eggs over plants. One female can produce several hundred eggs. The parents eat their own eggs, so the parents are normally removed after spawning. As with many fish, the black neon tetra often spawns in the early morning. Raising the fry can be more difficult because of their small size. The first food will normally be protozoa (infusoria), then Daphnia.

{{quote box | quote = "Fish eagerly read the terms and conditions. Many of us humans don't read the terms of service, but fish are smarter than we are" | source = – caption from Mutekimaru in a video about the incident In 2020, the fish beat Pokemon Sapphire after 3,195 hours, a feat that takes about 30 hours for a typical human. Mutekimaru later requested a refund of the 500 yen from Nintendo. Several media outlets facetiously described the fish as having committed "credit card fraud". After about seven hours, their movements shut down the Switch.