Crustaceans
Crustaceans, such as crabs, lobster and shrimp, all enjoy the protection from predators provided by coral reefs. They can hide between the branches of the coral, or in small crevices between rocks and coral. Some crustaceans even hunt their prey on reefs. Others, such as certain species of shrimp, eat parasites and dead skin found on fish in the reefs.
Mollusks
Many species of mollusks can be found living in coral reefs. Some are able to find food in the reef by filtering nutrients and food from the water. Others eat the animals they find there. For instance, some snails drill holes into the shells of clams and then eat them. Mollusks include clams, scallops, snails, squid and octopuses.
Octopuses are able to squeeze into the tiny cracks and crevices of the reef to avoid predators. If that fails, they actually can lose one of their arms and re-grow it later. They also can emit a black dye that helps them escape from a predator, or confuse prey before swooping in for an attack.
Fish
Many brightly-colored fish of all sizes like to hide in the coral, which can be as brightly-colored as they are. Predator fish will lie in wait for smaller fish to feed on. Large fish, such as sharks, eat crab, shrimp and fish and may call the coral reef home. Many fish, such as the parrot fish, eat algae right off the coral.
Fish leave bits of food and waste in the reef, which becomes food for smaller animals, and nutrients for plant life. Fish found in coral reefs include angelfish, seahorses, snappers, puffer fish, barracuda and butterfly fish.
Eels
Eels are built to navigate the tight crevices and cracks of a coral reef, and their prey is in great supply there. Eels have sharp teeth and powerful jaws that can snap up fish and even octopuses.
Sea Sponges
They may look like plants, but sea sponges are actually animals that can grow up to 6 feet in diameter. Sea sponges don't have vertebrae, tissues or organs; they are made up of chambers that connect to open pores on their surface. The pores filter food from the water. Sea sponges provide great hiding spots for small fish and other creatures.
