Blue discus
Symphysodon aequifasciatus
— Where the name comes from
Symphysodon is “symphysis tooth”, from sýmphysis, the point where the two halves of the lower jaw fuse: it carries a cluster of small teeth there. Aequifasciatus means “equally banded”. The common name, in every language, looks at the shape: a flat round disc as tall as a hand.
— Facts
- Group
- Fish · Actinopterygii · Chondrichthyes
- Order
- Cichlids
- Habitat
- Calm shaded water of the flooded forest, among the roots
- Range
- The central Amazon basin, Brazil and Peru
- Size
- 15–20 cm, 150–250 g
- Diet
- Insect larvae, crustaceans, plant detritus
- Lifespan
- 10 years, up to 15 in an aquarium
— Characteristics
- 01
The very deep thin body lets it slip between submerged roots.
- 02
It lives in groups with stable hierarchies.
- 03
It changes colour with mood, from washed out to deep brown.
— What sets it apart
The parents nurse. After hatching, the skin of both adults produces a dense secretion rich in protein and antibodies, and the fry attach to the flanks of father and mother and feed on it for two or three weeks; when one of them tires it gives a sharp flick and the brood passes to the other. The behaviour is known in very few fish, and chemical analysis has shown that the secretion changes composition as the young grow, exactly as mammalian milk does.
