Sea urchins, are typically spiny, globular animals, echinoderms in the class Echinoidea. About 950 species live on the seabed, inhabiting all oceans and depth zones from the intertidal to 5,000 metres. Their hard shells (tests) are round and spiny, usually from 3 to 10 cm across. Sea urchins move slowly, crawling with their tube feet, and sometimes pushing themselves with their spines. They feed primarily on algae but also eat slow-moving or sessile animals. Their predators include sea otters, starfish, wolf eels, triggerfish, and humans.
The Diadematidae are a family of sea urchins. Their tests are either rigid or flexible and their spines are long and hollow.
The diadema urchin or blue-black urchin is a species of tropical sea urchin, member of the Diadematidae family.
Echinothrix calamaris, known commonly as the banded sea urchin or double spined urchin among other vernacular names, is a species of sea urchin in the family Diadematidae.
The clearfin lionfish, also called the tailbar lionfish, radiata lionfish, fireworks fish or radial firefish, is a carnivorous, ray-finned fish with venomous spines that lives in the Indian and western Pacific Oceans. This is the only lionfish species which has spines without any markings. It can also be recognized by the pair of horizontal white stripes on its caudal peduncle.
Diadema setosum is a species of long-spined sea urchin belonging to the family Diadematidae. It is a typical sea urchin, with extremely long, hollow spines that are mildly venomous. D. setosum differs from other Diadema with five, characteristic white dots that can be found on its body. The species can be found throughout the Indo-Pacific region, from Australia and Africa to Japan and the Red Sea. Despite being capable of causing painful stings when stepped upon, the urchin is only slightly venomous and does not pose a serious threat to humans.
Algae eater, also called an algivore, is a common name for many bottom-dwelling or algae-eating species that feed on algae. Algae eaters are important for the fishkeeping hobby and many are commonly kept by hobbyists.
Meoma ventricosa, known by the common names cake urchin and red heart urchin, is a large species of sea urchin which lives in shallow waters in the Caribbean. It may reach a diameter of twenty centimeters and is covered in reddish-brown spines. It has both pentagonal radial symmetry and bilateral symmetry, giving it a sand-dollar appearance; however, two of its five sections are merged more closely than the others.
Heterocentrotus mamillatus, commonly known as the slate pencil urchin, red slate pencil urchin, or red pencil urchin, is a species of tropical sea urchin from the Indo-Pacific region.
Echinometra mathaei, the burrowing urchin, is a species of sea urchin in the family Echinometridae. It occurs in shallow waters in the Indo-Pacific region. The type locality is Mauritius.
Toxopneustes is a genus of sea urchins from the tropical Indo-Pacific. It contains four species. They are known to possess medically significant venom to humans on their pedicellariae. They are sometimes collectively known as flower urchins, after the most widespread and most commonly encountered species in the genus, the flower urchin. Species included in the genus are the following:
Dorippe frascone, the urchin crab or carrier crab, is a small species of crab in the family Dorippidae that was first described scientifically by J.F.W. Herbst, in 1785. It is found in the Red Sea and parts of the western and eastern Indian Ocean. It often has a symbiotic relationship with a long-spined sea urchin and carries one around on its carapace.
The blue blanquillo, Malacanthus latovittatus, also known as the banded blanquillo, striped blanquillo, false whiting, sand tilefish or eye of the sea, is a species of marine ray-finned fish, a tilefish belonging to the family Malacanthidae. It is found in the Indo-Pacific.
Diadema paucispinum, the long-spined sea urchin, is a species of sea urchin in the family Diadematidae. It is found in the western Indo-Pacific Ocean and in Hawaii and other east Pacific islands.
Brissus latecarinatus is a species of sea urchins of the Family Brissidae. Their armour is covered with spines. Brissus latecarinatus was first scientifically described in 1778 by Nathanael Gottfried Leske.
Diadema savignyi is a species of long-spined sea urchin belonging to the family Diadematidae. Common names include long-spined sea urchin, black longspine urchin and the banded diadem. It is native to the east coast of Africa, the Red Sea, the Indian Ocean and western Pacific Ocean. It was first described in 1829 by the French naturalist Jean Victoire Audouin. The specific epithet honours the French zoologist Marie Jules César Savigny who described many new marine species from the Mediterranean Sea and Red Sea. The type locality is Mauritius.
Clypeaster humilis is a species of sea urchin in the Family Clypeasteridae. This species was first scientifically described in 1778 by the German biologist Nathanael Gottfried Leske. It occurs in the tropical Indo-Pacific region.
Parechinus angulosus, the Cape urchin, is a sea urchin in the family Parechinidae endemic to southern Africa.
