This fish species has existed for 100,000 years. Every single one of them has been female.

The hybrid freshwater fish actually reproduces exclusively female clones, doing so for much longer than scientists thought ...
Science Daily

Fish adjust reproduction in response to predators

Some species of fish can evolve their egg-laying habits in response to predators in the area in order to survive, according to new research. Some species of fish can evolve their egg-laying habits in ...

This fish species survived 100,000 years without males. Scientists thought it should be long dead – but it's thriving

All-female species have been long thought of as evolutionary dead ends – but one fish has defied the odds to live without ...
EurekAlert!

Fish adjust reproduction in response to predators

Ranging in size from about 2 to 6 inches, the killifish are ideal for evolutionary studies because they are highly adaptable to their surroundings. Some types of killifish are even known to be ...