There are two known types of zooplankton, meroplankton, where their larval or reproductive stages are spent as a plankton, and holoplankton, organisms that are plankton their entire lives.
Zooplankton are a heavily favoured food by a large number of marine organisms. They are considered vital species as they are abundant and ubiquitous in the ocean. As they are predated by many, they have camouflaging abilities to avoid being consumed. Most are very transparent while some jellyfish are blue in colour as a survival mechanism.