Virtually all species of fish have been wiped out, leaving all the niches they filled vacant. Silverswimmers are the group that has evolved to make the most of this opportunity. Their ancestors were microscopic crab larvae, but now they are as diverse in size and shape as fish once were, and they fill the sea.
In the Global Ocean there are about 9,000 species of silverswimmers. They have flexible jointed legs, a tail that moves up and down to help them swim and a tough shell like covering to protect their bodies.
They are filter feeders meaning they sieve tiny sea creatures called plankton from the water to eat.
They no longer reach adult stage but reproduce as larvae. Every summer they lay thousands of eggs which float on the water for 4 days before hatching.