Development
In most gobies, eggs hatch in one to five days and grow rapidly within a few days. At hatching the larvae are quite advanced with pigmented eyes, well-developed jaws, digestive tracts, and vertical fin folds. The small transparent larvae (between 2 and 10 mm long) are usually dispersed in the water column where they swim for three to 20 days. Finally, the larvae settle into a suitable habitat and develop colors that allow them to blend in with the surroundings. They reach sexual maturity within a few months. However, in temperate climates development may take much longer, with sexual maturity occurring after one to two years.
A notable exception to this developmental pattern (and there are likely many others) can be found in burrowing gobies. In this species, the male remains in a burrow, which is sealed shut by the female, for up to five days. During this time, the burrow is periodically reopened and the eggs cleaned by both male and female before the male is again sealed in the burrow. The eggs develop entirely within the burrow and only one juvenile apparently exits the burrow, suggesting that juveniles receive nourishment through cannibalism, as well as food reserves and their surroundings. Upon exiting, the juvenile immediately begins a benthic existence.
