Sea goldies live in and around coral reefs in warm tropical oceans. These beautiful little fish are often seen in large shoals and add splashes of colour to the reef.
Look carefully and see if you can spot the differences between males and females.
Females are orange-gold with a blue stripe below the eye and males are reddish with an extended third dorsal spine.
Sex change on the reef
Many fishes have the ability to change sex. This is a strategy to maximise reproductive output. Some change from male to female while others change from female to male such as sea goldies.
This is the dominant reproductive style on coral reefs. On these reefs there is intense competition for the best spawning sites and large dominant males set up territories which are defended against all other males. The larger the male, the bigger his territory and the more females he will attract to spawn with. In this way millions of eggs can be fertilised by a single male. Smaller fish cannot compete for these sites so they remain female until they are large enough to compete and the opportunity arises.