Stingrays are a family of rays, cartilaginous fishes, related to sharks. They are common in coastal tropical and subtropical waters throughout the world. They are named after the barbed stinger (which is removed on the ones you can touch at the Aquarium) on their tail, which is used exclusively in self-defense. The stinger may reach a length of approximately 35 cm, and it's underside has 2 grooves with venom glands. The stinger is covered with a thin layer of skin, in which the venom is concentrated. Some species have several stingers, and a few, lack a stinger entirely.
Their flattened bodies allow them to effectively conceal themselves in their environment. Stingrays do this by agitating the sand and hiding beneath it. Stingrays eyes are on top of their bodies and their mouths on the underside, therefore they cannot see their prey; instead, they use smell and electro-receptors similar to those of sharks. Stingrays primarily on molluscs, crustaceans, and some small fish. They settle on the bottom while feeding, often leaving only their eyes and tail visible. Coral reefs are a favorite feeding ground and usually shared with the sharks during high tide.
Photo was taken with a Nikon D5000 18-55mm lens.