Discus fishes belong to the Cichlid family, a family of fishes which comes in a surprising diversity of shapes, sizes and colours. Discus fishes are derived from the many wild-occurring forms of two closely related species: Symphysodon aequifasciata and S. discus. Both species occur naturally only in the Amazon basin of South America. They are a brightly coloured fish; the colours greatly affected by mood, sex and hormonal chemistry. Huge advancements have been made in aquarium technology in recent years and this means that discus fish are now far easier to keep. But they are still difficult to maintain and require a lot of work.