This particular fish is a different species from the better known and more colourful neon tetra. It was discovered in a tributary of the Rio Paraguay in the Mato Grosso region of Brazil. The distinctive blackish area extends for a distance below the iridescent greenish-blue line on the fish's body, but does not color the fins. The upper part of the body is olive-green, while the underparts are silvery. The coloration of the black neon tetra can vary somewhat however, depending on the water condition and lighting. These tetras prefer rather dark surroundings and show to best effect in small group.

Occurring further south than its red relative, in parts of Bolivia and Brazil, this tetra has also prove to be more adaptable. It should be housed in a well-planted tank, with floating plants on the surface to ensure diffuse lighting. Be careful when purchasing stock to avoid any in tanks housing thin or sickly individuals, because black phantom tetras are susceptitle to piscine tuberculosis. If introduced to an aquarium, this likely to wipe out the occupants.

Tiger barbs are also sometimes called Sumatra barbs, although they do occur elsewhere in south-east Asia as well. They are probably the most widely kept of all barbs, and can be instantly recognized by the four black stripes crossing their body. Males are more colorful the females, with reddish tips to their fins and a redder tone to their faces. Tiger barbs can simetimes prove to be disruptive in a community aquarium, especially when housed with other fish which have elaborate fins, such as angelfish. These barbs often dispaly a tendency to nip at fins, damaging them as a result, so their companions need to be chosen with care. Well-oxygenated water is essential for tiger barbs; If the oxygen level is poor, the fish will cluster at the surface adopting an almost vertical posture.

This species is also known as the blue gourami because of its distinctive natural coloration, although various colour variants, most notably a golden form, have been developed as the result of domestication. The pointed dorsal fin of the mature male serves to distinguish the sexes in any event, irrespective of their coloration. These gouramis are very easy to care for, although they will not prove to be active tank occupants. Any companions therefore need to be chosen with are to ensure they will not persecute the gouramis, which is likely to result in a loss of color. Males must be kept separate because they can be aggressive towards each other.

A shoal of these fish is truly spectacular in a well-planted aquarium, although they can also be kept in the company of other non-aggressive fish of similar size. The neon tetra originates from the Rio Putumayo in easter Peru and when it first became available to aquarists in 1936, one of these fish would fetch a price equivalent to the average monthly salary at that time. Since then, they have been bred commercially in huge numbers and no longer command a premium price. Beware of purchasing any neon tetras which show loss of colration. This is an obvious symptom of the parastitic ailment popularly known as neon tetra disease, although the neon is not the only species which is at risk. Neon tetras will come to the surface to feed on flake food floating there, but they often prefer to seize food in the mid-water area when it is sinking. Once established these tetras can prove long-lived, with a life expectation of a decade or more.

Although the wild form of this fish is silvery-grey in color, the rose-pink domesticated variety is now more commonly available. Sexing by visual means is almost totally impossible outside the breeding period, when the female swells with eggs. These gouramis can grow to a relatively large size and are bred commercially, not only for the aquarium trade, but also as a source of food in various parts of south Asia. Kissing gouramis have thick lips which serve to help them browse on algae. They can be useful for this purpose in the aquarium but, unfortunately, they will also destroy vegetation. The strange way in which kissing gouramis touch lips is not part of the spawning process-instead, it probably allows territorial disputes to be amicably resolved without the need for more overt display of aggression.