More about egg-laying fish

By Rita:

In an earlier post I briefly described the most common egg-laying style of fish in a fish tank aquarium, egg scattering, and provided some insight as to why these eggs often did not reach adulthood.  In this post I will discuss some of the other egg laying strategies. Each group is presented in order of parental attentiveness to the offspring.

The egg scatterers have no parental interest in the eggs or the fry.  They are also likely to eat their own eggs after the spawn.

The egg hangers on the other hand are not as apt to eat their own eggs.   The spawning fish lay and fertilize each egg then hang them by a fine, sticky thread from plants usually near the top of the aquarium.  Beyond that there is no parental care.   This group of fish includes Lyretail, Panchax, Lampeye, and Rivulus plus others.  Most of this group is not common to the average tropical fish aquaria.  One of the reasons is they are among the more expensive fish. The expense is due to the fact that it takes more time and space for breeding. The female will lay up to 200 eggs over a 20-day period.  The young will then hatch in a staggered period according to the day laid.  This can result in a hodgepodge of growing fry.  The younger fry is in danger of being eaten by the earlier hatched larger fry.

Nest builders are the another group and they take a slightly more active parental role. The nest is first prepared either by sticking bubbles together or gluing aquarium debris into a nest.  The eggs will be deposited into the nest.  The nest is then protected until the eggs hatch.  Once the fry hatch they are on their own. The fish that comprise this group are the Sticklebacks, Siamese Fighting-Fish and Gourami.

The most protective of their eggs and off spring is the egg hiders and the egg anchorers.  This group consists mostly of Cichlids and Dwarf Cichlids.  It also includes Angelfish, Jack Dempsey and a few others.  As the group name implies the eggs are attached to a surface either secluded (the egg hiders) or in the open.  Both partners concern themselves with preparation of the spawning bed, the care and protection of the eggs, and the care of the fry for a period of time after hatching.

To leave a pair of spawning fish in a community tank is always a risk. A properly prepared breeding tank would greatly increase the chances of having viable young.

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