Morphological and behavioral ontogeny in larval and early juvenile discus fish Symphysodon aequifasciatus.

Satoh, Shun; Tanoue, Hideaki; Ruitton, Sandrine; Mohri, Masahiko; Komatsu, Teruhisa

We observed the growth, morphological changes, and behavior of larvae and juveniles of the Amazonian substrate-brooding cichlid discus fish Symphysodon aequifasciatus under laboratory conditions. The mean body length (BL) of newly hatched larvae was 3.4-3.5 mm, and the yolksac extended to approximately 42 % of their BL. Larvae detached from the substrate on day 4 began swimming and immediately displayed biting behavior on the body surface of the parents. Larvae had completely consumed their yolksacs by day 7. They began swimming at an earlier developmental stage compared with other cichlid species. Their thick lips may be advantageous for removing mucus from the bodies of the parent fish. Juveniles actively fed on Artemia spp. by day 30, and the frequency of biting behavior toward the parents decreased between days 20 and 35. Bone ossification was essentially complete in juveniles by day 32. Juveniles reached 16.0 ± 1.1 mm BL by day 35. These results indicate that the morphology and behavior of larval and early juvenile S. aequifasciatus exhibit adaptations for mucus provisioning.

DISCUS (Fish); FISH morphology; FISH behavior; ONTOGENY; FISH larvae

Ichthyological Research, 2017, Vol 64, Issue 1, p37

1341-8998

Academic Journal

10.1007/s10228-016-0530-y