Few fish are famed for their parenting skills. Most species leave their freshly hatched fry to fend for themselves, but not discus fish. Jonathan Buckley from the University of Plymouth, UK, explains that discus fish young feed on the mucus that their parents secrete over their bodies until they are big enough to forage.
Most aquarists know that young discus graze the mucus from the sides of their parents so this article will come as no surprise. Rather more interesting is the discovery of changes in the composition of the mucus produced by the parent fish.
Buckley found a huge increase in the mucus’ antibody and protein levels when the parents laid their eggs, similar to the changes seen in mammalian milk around the time of birth. The protein and antibody levels remained high until the third week and returned to pre-spawning levels during the fourth week after hatching.
Much as human infants get extra protection from breast-feeding so to do young discus fish benefit from the “milk” they get from their parents. Any discus breeder will confirm that fish reared away from their parents rarely do well.
Read the full article here.