Bitterlings

A considerable number of beasts shroud their eggs to keep them at a distance from the nosy eyes of predators. Bitterlings do this, but they go a fascinating step further by laying their eggs in a most unusual place.

While alternate fish lay their eggs right around the rock of a stream, scatter them among fine-leaved plants, or even carry them inside their own bodies, few go as far as bitterlings. These fish lay their eggs inside another animal. The unsuspecting foster parent can do nothing about this. It cannot swim away, attack the intruding bitterling, or even protect itself. It simply has to accept its fostering duties.