Beginner Crabs

Crabs quickly capture the heart with their awkward posture and walking style. Their large claws can tear apart meat or capture small plankton. With diets ranging from coral to algae to meat, there are a wide variety of crabs for all ranges of aquarium experience. Their bright colors, methods of camouflage, and unique shapes can keep you entertained for hours. Here are some of crabs suitable for beginners.

Sub-Species for Aquariums:

Arrow Crab – Also known as the Spider Crab because of its long legs, this is a relatively large and decorative crab. It can grow to be up to ten inches with females dramatically smaller than males. They are often found in the crevices of reefs. They are semi-aggressive and will attack some shrimp and slow moving fish. The Decorator Arrow Crab has small spines on its legs that it will “decorate” with algae, coral, and small rocks in order to camouflage itself. Arrow Crabs are carnivores.

Horseshoe Crab – Not a crab at all, this creature is more a mite than a crab and will do an excellent job foraging through the sandy bottom of your tank searching for worms and organic debris. They move constantly and can grow to be twelve inches in diameter! Because of their size, they can be a bit bothersome in the tank, like a bull in a china shop, but they are quite peaceful and any damage done is accidental. Horseshoe Crabs are carnivores.

Spider Decorator Crab – Though it may seem harmful to the coral reef at the start, this crab is excellent at helping to propagate your coral throughout the tank. This crab loves to decorate itself with bits of coral to help camouflage while it hunts at night. In a large tank, this means that the coral will travel via the crab from one location to another, giving it a chance to grow in a new location. Spider Decorator Crabs are Carnivores.

Crinoid Squat Lobster – Often found hitch-hiking on live rock and coral, these small nano-inverts are completely reef-safe and very peaceful. While they are often found on or around Crinoid Feather Sea Stars, they thankfully do not require the Sea Star in order to survive as they are quite hardy and will happily accept a number of foods. Do not keep two of the same gender in a tank. Crinoid Squat Lobsters are carnivores.

Crabs do best in tanks with soft, sandy substrates and lots of live rock and coral to live among and hide inside. Nooks and crannies are a must! Some crabs are semi-aggressive and will attack other invertebrates such as shrimp or slow moving fish, so care should be taken when adding them to a community tank.


These crabs are carnivores and opportunistic feeders. They will accept most meaty flake and tablet foods as well as fish and shrimp meat. If they are not receiving enough nutrition, some will begin to pick at polyps.

Size: 10 Inches
Freshwater/ Saltwater: Saltwater
Diet: Carnivore
Reef Compatibility: 3
Tank Mate Compatibility: 3

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