Stingray
Dasyatidae species

Stingrays inhabit shallow water, especially in the tropics, but in temperate regions as well. All have a distinctive ray shape, but coloration may make them hard to spot unless they are swimming. The venomous, barbed spines in their tails can cause severe or fatal injury.

Rabbitfish
Siganidae species

Rabbitfish are found predominantly on the reefs in the Pacific and Indian oceans. They average about 30 centimeters (12 inches) long and have very sharp spines in their fins. The spines are venomous and can inflict intense pain.

Scorpion fish or zebra fish
Scorpaenidae species

Scorpion fish live mainly in the reefs in the Pacific and Indian oceans. They vary from 30 to 90 centimeters (12 to 35 inches) long, are usually reddish in coloration, and have long wavy fins and spines. They inflict an intensely painful sting.

Siganus fish

The siganus fish is small, about 10 to 15 centimeters (4 to 6 inches) long, and looks much like a small tuna. It has venemous spines in its dorsal and ventral fins. These spines can inflict painful stings.

Stonefish
Synanceja species

Stonefish are found in the tropical waters of the Pacific and Indian oceans. Averaging about 30 centimeters (12 inches) in length, their subdued colors and lumpy shape provide them with exceptional camouflage. When stepped on, the fins in the dorsal spine inflict an extremely painful and sometimes fatal wound.

Tang or surgeonfish
Acanthuridae species

Tang or surgeonfish average 20 to 25 centimeters (8 to 10 inches) in length, with a deep body, small mouth, and bright coloration. They have needlelike spines on the side of the tail that cause extremely painful wounds. This fish is found in all tropical waters.

Toadfish
Batrachoididae species

Toadfish are found in the tropical waters off the coasts of South and Central America. They are between 17.5 and 25 centimeters (7 to 10 inches) long and have a dull color and large mouths. They bury themselves in the sand and may be easily stepped on. They have very sharp, extremely poisonous spines on the dorsal fin (back).

Weever fish
Trachinidae species

The weever fish is a tropical fish that is fairly slim and about 30 centimeters (12 inches) long. All its fins have venomous spines that cause a painful wound.

Blue-ringed octopus
Hapalochlaena species

This small octopus is usually found on the Great Barrier Reef off eastern Australia. It is grayish-white with iridescent blue ringlike markings. This octopus usually will not bite unless stepped on or handled. Its bite is extremely poisonous and frequently lethal.

Portuguese man-of-war
Physalis species

Although it resembles a jellyfish, the Portuguese man-of-war is actually a colony of sea animals. Mainly found in tropical regions; however, the Gulf stream current can carry it as far as Europe. It is also found as far south as Australia. The floating portion of the man-of-war may be as small as 15 centimeters (6 inches), but the tentacles can reach 12 meters (40 feet) in length. These tentacles inflict a painful and incapacitating sting, but it is rarely fatal.

Cone shells
Conidae species

These cone-shaped shells have smooth, colorful mottling and long, narrow openings in the base of the shell. They live under rocks, in crevices and coral reefs, and along rocky shores and protected bays in tropical areas. All have tiny teeth that are similar to hypodermic needles. They can inject an extremely poisonous venom that acts very swiftly, causing acute pain, swelling, paralysis, blindness, and possible death within hours. Avoid handling all cone shells.

Terebra shells
Terebridae species

These shells are found in both temperate and tropical waters. They are similar to cone shells but much thinner and longer. They poison in the same way as cone shells, but their venom is not as poisonous.