9 Top Marine Hermit Crabs for Reef Tanks

Not all hermit crabs are considered safe for reef tanks. In fact, many hermit crabs are known to destroy corals, eat other invertebrates, and even eat fish. However, there are some options that can coexist in a reef tank. These hermit crabs are fairly small species that won't disturb the other tank life. They can squeeze into the cracks and crevices that larger crabs can't to eat algae and other debris that otherwise would pollute the tank water.

Here are nine hermit crab species that are safe for marine reef tanks.

Tip

Growing or molting hermit crabs are always on the lookout for a larger shell to settle in, so large snails in your tank might not be entirely safe. Have many empty shells always available for the hermit crabs to choose from.​​

  • 01 of 09

    Dwarf Blue Leg Hermit Crab

    blue leg hermit crab
    Madelyn Catob

    Native to the Caribbean, the dwarf blue leg hermit crab is a great addition to a saltwater aquarium because it eats many kinds of algae, including red slime algae (cyanobacteria). It sifts and aerates the sand as well. This tiny crab likes to live in abandoned snail shells, so it might be a threat to a snail in your tank unless you provide it with empty shells. Members of this crab's genus are sometimes called equal-handed hermit crabs because both claws are the same size.

    Species Overview

    Length: Up to 1.5 inches

    Physical Characteristics: Blue legs with red banding and white tips; both claws are of equal size

  • 02 of 09

    Dwarf Red Tip Hermit Crab

    The dwarf red tip hermit crab is native to the coastal waters around Central America. In home aquariums, this hermit crab prefers sand in which it can forage and dig.​ It is known for its scavenger tendencies and will do an excellent job cleaning all the crevices of a tank to control algae growth while aerating the sand. 

    Species Overview

    Length: Up to 2 inches

    Physical Characteristics: Bright red face and legs; both claws are of equal size

  • 03 of 09

    Dwarf Yellow Tip Hermit Crab

    The striking dwarf yellow tip hermit crab comes from the coastal waters around Vietnam. Its small size allows it to get into all of the nooks and crannies of a reef tank. It's a ravenous algae eater that likes to dig through sand. So it does best in an established tank that has ample algae for it to graze on.

    Species Overview

    Length: Up to 1 inch

    Physical Characteristics: Bright yellow bands on green to black legs; both claws are of equal size

  • 04 of 09

    Dwarf Zebra Hermit Crab

    dwarf zebra hermit crab

    Joe Martin

    The dwarf zebra hermit crab is popular in home aquariums for its distinct coloring. It's native to intertidal regions of the Pacific Ocean. This hermit crab is also a voracious algae scavenger, including for red slime algae. If there's not enough algae in the tank, its diet should be supplemented with dried seaweed.

    Species Overview

    Length: Up to 1 inch

    Physical Characteristics: Colored pincers; white or orange bands on otherwise dark legs; brilliant blue eyestalks fading into an orange-tinged upper half; larger left claw

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  • 05 of 09

    Polka Dot Hermit Crab

    The polka dot hermit crab is another algae and leftover food scavenger that can squeeze into tiny areas of a tank to keep them clean. This hermit crab won't bother corals. But it might attack a snail for its shell. So make sure you offer plenty of empty shells in your tank. For the most part, though, it's a peaceful crab.

    Species Overview

    Length: Up to 1 inch

    Physical Characteristics: Larger right claw; red body with white dots

  • 06 of 09

    Electric Orange Hermit Crab

    electric orange hermit crab

    Keoki Stender

    Originating in the Hawaiian Islands, the electric orange hermit crab is a great addition to a saltwater aquarium because it eats uneaten food, many kinds of algae, and other debris and waste. It also sifts and aerates the sand as it forages. Offer it dried seaweed when there's not enough algae in the tank for it to eat.

    Species Overview

    Length: Up to 2 inches

    Physical Characteristics: Vivid orange legs with brown bands; blue eyes

  • 07 of 09

    Halloween Hermit Crab

    Halloween hermit crab

    Larry Yarbray

    Also native to the Hawaiian Islands, the Halloween hermit crab is named for its vivid orange and red leg bands that make it look like a Halloween decoration. It eats various types of algae, including green hair algae and cyanobacteria, along with leftover food and other debris. It can get relatively large compared to some of the dwarf hermit crabs, so it could potentially disrupt corals in a reef tank. But overall it peacefully coexists in a tank.

    Species Overview

    Length: 2 inches

    Physical Characteristics: Alternating orange and red bands on legs; orange eyestalks

  • 08 of 09

    Scarlet Reef Hermit Crab

    scarlet reef hermit crab

    Craig Smith

    Native to the Caribbean and Indonesia, the scarlet reef hermit crab is named for its brilliant red body. It's also known as the red reef hermit crab or red-legged hermit crab. This is a hardy and hungry little crab that feeds on algae and debris in reef aquariums. In fact, it specifically likes the types of algae that can be problematic growers in tanks. This hermit crab also is known for its friendly nature toward its fellow tank inhabitants.

    Species Overview

    Length: Up to 1.5 inches

    Physical Characteristics: Bright red legs; yellow face

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  • 09 of 09

    Elegant Hermit Crab

    Hawaii elegant hermit crab

    This species from Hawaii is a large hermit crab. Although it won't eat corals, it might damage them by dragging its big heavy shell over them. It also might attack an aquarium snail for its shell if you don't provide empty ones. But it will do an excellent job at keeping the tank's algae growth in check and removing debris and waste. 

    Species Overview

    Length: Up to 3 inches

    Physical Characteristics: Blue, red, or yellow knuckles on brown legs; long eyestalks with blue on the lower half and orange on the upper half; larger left claw