Some amazingly talented camouflage artists thrive in the ocean -- a cuttlefish, for example, can change color or shape to match its surroundings. Starfish don't actively camouflage themselves by changing color or shape, but some have natural exoskeleton irregularities that help hide them from predators.
Starfish come in a rainbow of colors. Many have color variations on their exoskeletons that look surprisingly like water and light moving over a coral reef -- fine camouflage for a creature who enjoys reef life. Brightly colored starfish can liven up your aquarium, and mottled ones can lead you on a merry game of hide-and-seek at feeding time as they blend in with the rock or reef.
Ridges and Bumps
Most starfish have bumpy skin, which can be small protrusions, large ridges or pointed spikes. This gives their exoskeleton an irregular texture, which helps them blend in with the craggy look of reefs or rocky ocean bottoms. The ridges and bumps are often a different color than the rest of the exoskeleton, helping add to the camouflage.
The long, spiky legs of a starfish help conceal it from predators as it hides among the reef. Coral tends to develop spiky growths of its own, and a starfish can look like an extension of the coral when a predator swims by. To predators attracted to shiny scales, round bodies and movement, the starfish is well-concealed among coral spikes.
Camouflage is not foolproof. Starfish succumb to predators such as large crabs, sharks, triggerfish and giant Triton snails. Although it's unlikely your aquarium has these animals large enough to attack your starfish, it might have another major predator: other starfish. Large starfish can chase down -- slowly -- smaller starfish and attack them. Prey starfish often detach an arm to escape, but it doesn't alway save them. Keeping your starfish well-fed can help keep them from attacking each other.