Hermit Crabs

Are hermit crabs essential for your reef?

The answer is no, they are not essential, but a few may be beneficial.

The reasons I say this are as follows:

1. All crabs are partially predatory. The bigger ones are definitely a problem in this regard.



2. Some animals such as corals need to be spot fed and hermits can go after this food, removing it from the coral. This is bad in two ways. First, they take the food and in doing so, they crawl over the coral.



3. Some will attack and kill small snails and use the new shell as a replacement.



4. Some will even attack each other.



5. Lastly, they are known to attack beneficial worms that live in your sand.

After reading that, you probably think all hermits are bad, but that is not true.

I have had success with a few species and still have them in my tanks today.

Please remember all the species are scavengers and will eat just about anything they can find. You need to choose them carefully to make sure they are reef safe and don’t grow very big.

The scarlet hermit crab is one of the most popular hermits for your reef aquarium.

It has a very colorful appearance, with scarlet red legs and body with yellow eyestalks, hence the name. Also, they eat all kinds of nuisance algae including red, green, and brown slim as well as green hair algae. They are also known to be good sand sifters.

In order to grow, this species must molt. This usually occurs at night. It’s actually pretty neat to see it. The crab will crawl out of its shell and lie on its back. Then it will exit its exoskeleton. A new exoskeleton is excreted that will take several hours to harden. While this goes on the animal is vulnerable from other would be predators. Please do not disturb him.

After the molting process, they will sometimes seek out a new shell if the old one isn’t big enough.

Scarlet hermits will grow to about 1 1/4 inches

Proper iodine levels need to be maintained to aid with successful molting.

It’s a good idea to add several empty shells of various sizes to your reef. This will hopefully supply your crab with many options for a new shell as he grows.

They are also known as the Hawaiian Reef or Dwarf Zebra.

Many people choose them because of their great coloration. He has orange and sky-blue eyestalks with black and white pincers, and white bands on the otherwise darker legs. He is a small crab that grows to only about one inch.

This crab would be a valuable addition to your aquarium. It eats many kinds of algae, including red slime algae (cyanobacteria), and sifts the sand, as well.

He requires good water quality to survive and flourish. As usual, you must supply additional shells of varying sizes, since they will need to move to new homes as they grow.

The blue legged hermit crab, also known as Dwarf Blue and Equal-Handed, is considered to be reef safe.

They have blue legs with orange/red joints, a blue face and bright orange antennae. They eat filamentous and cyanobacteria (red algae) algae as well as uneaten food.

These guys will only grow to about 1 inch. Although they are considered semi-aggressive and have been known to occasionally kill and eat snails, as long as you provide an assortment of empty shells, you should have no problems.

I would not house them if you have stony corals. They have sharp feet that may damage the corals.