Neon Tetras
The blue stripe is reflective rather than pigmented, which is why it flares under a light. A shoal of a dozen behaves nothing like three.
Overview
Neon tetras come from blackwater and clearwater tributaries of the Solimoes, they reach about 2.5 cm, and the water they come from is extraordinarily soft. FishBase gives a hardness range of 1 to 2 dH and a pH of 5.0 to 7.0, along with 20 to 26 degrees C, which is 68 to 79 F.
They are cooler and softer water fish than the community tanks they usually end up in, and that mismatch is behind a great deal of the reputation neons have for dying without explanation.
Temperament
A shoaling fish and nothing else. Alone or in threes a neon hides, loses colour and stops eating, and in a proper group it holds formation in open water and is visible all day.
A shoaling study on this species counted the smallest functioning unit at six to eight fish, and ten or more in a tank looks and behaves better again. Nothing about them is aggressive. They are, however, exactly mouth sized for angelfish and other mid sized cichlids, which is a pairing shops still put side by side.
Care and grooming
Worms, small insects, crustaceans and plant matter in the wild, so micro pellets and crushed flake, with frozen brine shrimp or daphnia as a change.
Soft, slightly acidic, dimly lit water suits them, and stability suits them more. Neons are sensitive to being moved and to sudden changes in chemistry, so acclimatising slowly over an hour rather than minutes is the single most useful thing a new keeper can do with them.
Living and exercise
A 60 cm tank, roughly 10 gallons, planted, with driftwood and floating cover to cut the light. Dark substrate makes the colour read properly and makes the fish bolder.
They use the middle of the water column, so they pair naturally with corydoras below them and leave the surface to something else. Tank mates should be small and calm, and warmth tolerance is worth checking: neons sit at the cooler end of tropical and are not comfortable in a discus tank.
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