Millions of tiny zooplankton (zoh-plank-tin) are visible to predators in bright light.  During the day they move down to the darker depths of the sea, beacause they don't want to be eaten.  "plankton" comes from a geeek word that means drifting.  Plankton may be small, but without them, the corals and other sea life would not exist.Some zooplankton look like minitures of the adults they will become, like a shrimp larva.   Plankton generally have limited or no swimming ability; instead, they are transported by tides and currents.  The zooplankton community is composed of both primary consumers (which eat phytoplankton) and secondary consumers (which feed on other zooplankton). Nearly all fish depend on zooplankton for food during their larval phases, and some fish continue to eat zooplankton their entire lives.