Hmmm... this thread seems appropriate...
So today I read up in a book on a kind of fish called the Stickleback.
To reproduce (which is complex with this species), the male will build a cup shaped basket out of leaves and twigs held together and attached to vegetation by a membrane he secretes. To attract the female he does a dance around her (displays may vary according to species) and then she goes into the nest, then he will get busy with her. When the eggs are released the male will catch any that fly away with his mouth and return them to the nest. When the deed is done he shows the female the door and forces them the f**k out.
Now the male will spend his time protecting the eggs and the young of the nest (up to around 4 nest could be guarded by a single male)... while any females may attempt to raid the nests and eat the eggs for a meal. But the male will either lure them away from the nests by distracting them by exposing his shiny belly, do an aggressive display, or just beat the crap out of any intruders (I think it varies according to species), to protect the children.
That is the relationship advice of the Stickleback.
Lousy husband, awesome father.
It is one of the most studied families of fish because of it's unique reproductive behaviour.
