Sea goldie

A dominant male in charge

The sea goldie is a beautiful orange fish that lives in shoals. If you take a close look in the aquarium, you can see a slightly larger fish that is pink rather than orange, swimming along with the orange fish. The orange fish are females, and the pink fish is a male, all of which are sea goldies. He is dominant, which means that he is the leader of the shoal. He alone is allowed to fertilise the eggs of the females. 

They are all born female

The sea goldie is a so-called protogynous hermaphrodite. It sounds complicated! Protogyn means ”female from the beginning” and hermaphrodite refers to organisms with both male and female reproductive organs. By ”protogynous hermaphrodite” we mean that all sea goldie individuals are born as females, but have the ability to change sex to male later in life. The sex change occurs when the male of the shoal dies or disappears in some other way. This triggers the most dominant female in the shoal to change sex to male, a process that takes between 2 and 4 weeks. The fish becomes larger, changes colour, the fin rays lengthen, and it starts producing sperm instead of eggs.