Angelfish
A tall bodied cichlid from the Amazon that swims among stems rather than in open water. Pairs form on their own and defend the spot they choose to spawn on.
Overview
The freshwater angelfish is a cichlid from the Amazon basin, and almost everything people find surprising about it follows from that. It is not a peaceful community fish that happens to be pretty. It pairs off, it claims a corner, and it defends that corner against whatever it decides is a rival.
It is also built the wrong way round for most aquariums. FishBase records 10.5 cm as the usual length and 15 cm as the maximum, but the body is deep rather than long, so a tall tank suits it and a shallow one does not. The recommended minimum is a 100 cm aquarium, which is about 29 gallons.
Temperament
Sociable while young and territorial once mature. The usual pattern is a group of five or more that gets along until two of them pair up, at which point the pair takes a corner and the rest of the tank learns where the line is.
Angelfish are attentive parents. Both fish guard eggs laid on a leaf or a flat surface, and the pair bond holds through brooding. Small fish that fit in a mouth are treated as food rather than as company, which is why neon tetras and adult angelfish are a bad pairing however often they are sold together.
Care and grooming
Flake, frozen and live food, fed in small amounts rather than one large one.
Water is the real work. FishBase gives a pH range of 6.0 to 8.0 and 24 to 30 degrees C, which is 75 to 86 F, and the important part is holding whatever number you pick rather than chasing an ideal. A biofilter takes up to eight weeks to establish in a tropical tank, and ammonia or nitrite readings above zero during that period are the single most common way a new angelfish tank fails.
Living and exercise
Height first, length second. A tall tank lets an adult sit upright without its fins folding, and dense planting or driftwood gives the non breeding fish somewhere to be that is not the pair's corner.
Tank mates are chosen by size and by temperament, not by looks. Anything small enough to swallow eventually gets swallowed, and anything that nips long fins will find plenty to nip. Corydoras and similar bottom fish generally work because they stay out of the disputed water entirely.
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