Neon tetras reach 4 cm in length, and are considered easy to keep in a community aquarium of at least 50 cm (20 in) long, with a pH of 6.0 to 6.5 and a KH of 1.0 to 2.0. However, they will die if traumatized by dramatic changes to their environments. They tend to be timid and, because of their small size, should not be kept with large or aggressive fish which may bully or simply eat them. Fish that mix well in an aquarium are guppies, other types of tetras, such as the rummy-nose tetra, cardinal tetra, and glowlight tetra, and other community fish that live well in an ideal tetra water condition. Mid-level feeders, they are best kept in schools of six or more, for the shoaling effect when they move around the tank. They shoal naturally in the wild and are thus more brightly colored and more active when kept as a shoal as opposed to singly. The color and the iridescent stripe of this fish may become dim at night, and can be virtually invisible after a period of darkness. The color may also fade during a period of stress, such as human intervention into the tank. Neons are best kept in a densely planted tank with subdued light and an ideal temperature of 21–27 °C (70–81 °F) to resemble their native Amazon environments.

Neon tetras are omnivores and will accept most flake foods, if sufficiently small, but should also have some small foods such as brine shrimp, daphnia, freeze-dried bloodworms, tubifex, which can be stuck to the side of the aquarium, and micropellet food to supplement their diets. A tropical sinking pellet is ideal, as most brands of these include natural color enhancers that bring out the color in neon tetras. Some frozen foods, including frozen blood worms, add variety to their diets.

It is an anadromous species and spawns in freshwater, often in rice paddies during the rainy season, earning it its common name. It also spends time in lagoons, estuaries and coastal rivers, in which it lives in burrows in the river bottom and bank. Males can reach a maximum total length of 100 centimetres, but more commonly reach a TL of 70 cm.

The Rice-paddy eel is of minor commercial interest to fisheries; it is caught in bag nets and marketed fresh. Its diet consists of bony fish and crabs such as Uca annulipes; as a nocturnal creature it forages actively during the night.

The red-tailed black shark (Epalzeorhynchos bicolor; syn. Labeo bicolor), also known as the redtail shark and redtail sharkminnow, is a species of freshwater fish in the carp family, Cyprinidae. It is endemic to Thailand and currently critically endangered, but common in aquaria, where it is prized for its deep black body and vivid red or orange tail. The red-tailed black sharks seen in the aquarium trade today are all captive bred. It is not closely related to sharks.

The black neon tetra (Hyphessobrycon herbertaxelrodi) is a freshwater fish of the characin family (family Characidae) of order Characiformes. It is native to the Paraguay basin of southern Brazil. This species is of typical elongated tetra appearance; it is of plain basic coloration but with two distinct, adjacent longitudinal stripes, white above black. The eye has two thin but distinctive color bands across the top, red above yellow. It grows to a maximum overall length of approximately 4 cm (1.6 in). The fish's natural diet consists of small invertebrates and plants. Black neon tetras should be kept in soft acidic water, which should be kept clean at all times. Their tank should contain live plants, a darker substrate and open water for swimming. Black neons should be kept in groups of at least 4−6. The Black neon tetra requires the following aquarium conditions: pH 5 - 7 dH (hardness) 1 - 2 Temperature 20–26 °C (68–79 °F) These fish swim at the top level of the aquarium, and do not feed from the bottom of the tank. Therefore, it is recommended they be kept with bottom dwelling fish (such as pygmy corydoras) so that leftover food is then eaten up off the substrate and not left to waste. Black neon tetras can be fed a variety of foods, including flake, frozen and freeze dried food. Small live foods like worms and brine shrimp are also recommended as they bring out the fish's colours.

The black sharkminnow (Labeo chrysophekadion), also known as the black shark or black labeo, is a species of freshwater fish in the carp family. It is found in the Mekong and Chao Phraya river basins, Malay Peninsula, Sumatra, Java and Borneo. It can reach a length of 90 cm (3 ft) and a weight of 7 kg (15 lb). It is sometimes seen in the aquarium trade.

These are extraordinary fish! These catfish share many attributes with the Siamese Fighting fish. Just like the Bettas, these fish come to the surface to "breathe" atmospheric air. Not only do they breathe air, but they also breed much the same way that Bettas do. They actually "build" bubble nests at the surface. The male guards the nest and takes care of the eggs. These peaceful fish will reach lengths of up to 6" in an aquarium, so they are suitable for larger aquariums and like sized tank mates.

Description This catfish is named for the way it looks as it swims through the water. It’s shark like swimming motion with it’s high dorsal fin gives it an intimidating look. The Blackfin shark is not an aggressive fish, but it does have a very large appetite. It also has a fairly large size. This combination makes it necessary to house this fish with fish at least 2″ or larger. Also, because this fish is a catfish, it lacks scales and requires some salt in the water to help keep it healthy. Usually, 1 table spoon of salt for every gallon of aquarium water would suffice. The Blackfin shark would also live very comfortably in a Brackish water aquarium.