Page 233 - Encyclopedia of Aquarium and Pond Fish, 3rd Edition

REPRODUCTION AND BREEDING 231

This is a risky breeding strategy, since a large proportion of eggs
and fry perish. Females lay almost daily during the spawning
period, producing hundreds of thousands of eggs to increase the INVERTEBRATE BREEDING
chances that at least some of their offspring will survive. Crustaceans and mollusks are rarely bred successfully in aquariums: the
factors that trigger breeding are difficult to duplicate in tanks, their
Parental care in marine species offspring are devoured by other tank occupants; and the ultraspecific
Some species, such as clownfish, gobies, and damselfish (see food needs of the young make rearing nearly impossible.
Invertebrates such as sponges, anemones, starfish, and corals fare
pp.240–243) are egg-depositors. These fish lay their eggs close better, since they can reproduce asexually, with pieces dividing off
to the substrate or on the reef, attaching them to rocks or from an existing colony or individual and developing into new
laying them in caves or shells. They produce far fewer eggs than organisms. In the wild, they also reproduce sexually, releasing
egg-scatterers but ensure a higher survival rate by guarding the eggs and sperm into the open water, as seen in the corals below.
eggs until they hatch. The well-formed fry then swim to the
surface, where they feed and develop before returning to the
reef. Other species, including jawfish (see p.282), are mouth-
brooders, collecting the eggs in their mouths and incubating
them there. Mouth-brooding species often lay fewer than 50
eggs, simply because they cannot fit any more in their mouths.
Sea horses and pipefish (see p.279) carry their eggs.

Powder Blue Tangs naturally live in large shoals.
One benefit of shoaling is that it makes it easier to
find a partner of the opposite sex.

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