Also known as African Red Knob Sea Star, African Red Knob Starfish, Horned Sea Star, Horned Starfish, Red Know Sea Star, Red Knob Starfish, Red-knobbed Starfish, Redspine Sea Star, Redspine Star, Redspine Starfish, Red-spined Sea Star, Red-spined Star, Red-spined Starfish, Spine-tipped Sea Star, Spine-tipped Star, Spine-tipped Starfish, Starfish.
Found singly or in groups on shallow gravel, sand and seagrass beds of coral and rocky reefs. Large sea star, with five conical, short, thick arms.
They feed nocturnally on clams, soft corals, sponges, other starfish and tube worms.
Length - 30cm
Depth - 0-40m
Sea Stars have remarkable regenerative powers, when attacked and damaged by predators they are able to grow new arms. They usually have five arms but have been found with 4 or 6 arms, this may be because more than one arm has been damaged at one time!
Sometimes small parasitic limpets can be found on the underside of arms which can deform the arms.
They possess a cleverly evolved arsenal of hydraulic tube feet connected to an elaborate water-vascular system that encircles the animal's mouth and extends via five radial canals down the centre of each arm.
Their mouth is underneath, but their prey is absorbed outside their mouths by forcing out their digestive organs from their stomach.
Sea Stars are carnivores and feed on almost any food including molluscs, worms, detritus and each other!
Some sea stars like the crown of thorns can be venomous. Ref: https://en.wikipedia.org/wiki/Protoreaster_linckii