There are certain fish which present serious dangers even to man because of their strength and ferocity. The shark is an obvious example, but among the most dangerous are the poisonous fish which use their venom in a number of ways.

Some have their flesh completely impregnated in poison and any attacker who bites them or eats them will die. Other fish impregnate their eggs with poison to protect their unborn young.

There are also fish with spines of fins that contain poison and others with teeth that carry venom, just like snakes.

The most unusual weapon belongs to the stingray. This is a strange, flat fish that spends much of its time on sandy or muddy bottoms of shallow waters where it is almost invisible. Most sting rays inhabit warm seas, but a few kinds are found in the rivers of South America.

If the fish is trodden on it lifts its tail which contains a long, poisonous sting that is usually kept in a sheath. This sting can inflict serious wounds, especially when the long, thin tail is lashed. The poison is painful; it can paralyze and, in some cases, prove fatal.