Fish are found in an extraordinary range of habitats, from mountain streams to hot springs and at depths below 7,000 meters. There are some 20,000 species of fish and the Maldivian reefs and seas boast of over 2,000 species.
Fish show amazing diversity and are unique in their variety of breeding and development patterns. They possess specialized sensory organs, nostrils, eyes, nerve endings or other senses to gather information. Fish can also monitor temperature, light, colour, dilution, gases, pressure or depth, water currents, vibrations, etc. External fertilization is common where the male fertilizes the eggs laid by the female and left to develop. The fish also has the ability to live with an array of other species forming symbiotic or other relationships.