Have you ever seen coral fish? As a rule, they are bright and bold and rather pretty creatures. But everything is not that easy and some scientists claim colour of fish is probably a form of communication, and some of them are already known to people …

Fish colour is a very useful thing, because it helps this or that fish to find mates and then tells the rest of the animal world dwellers information about this particular creature: whether it is dangerous or not, for example.

What is more, fish can either brighten or darken their hues and in this way they express appreciation and aggression or fear correspondently. It is a big problem that people and other animals don’t understand these important sings.

There are a lot of fish that ‘glow’ in the ultra-violet and it is a kind of self-defense, because they are to some extent invisible to people and seen by other fish.