Crab meal: What do crabs eat at home? They have a floating island so they can get out of the water and hopefully not out of the tank. Sand is important because they need to be able to sift through it to feed and burrow. However, others are active predators, and will eat anything they can catch. Scarlet Reef Hermit Crab: Named for their bright red coloration, the scarlet reef hermit crab is particularly popular in reef tank environments. Fiddler crabs make great pets, especially for someone seeking a “best bang for the buck” solution. I had about 12 of the little snails that usually come on live plants and I noticed the Crabs eating them so they are keeping them under control in my tank. Besides, they may attack or eat other tank inhabitants. As for eating the other fish. May catch and eat small fish, dwarf African frogs and other tank mates that live or sleep on the bottom of the tank. But it's important to know what saltwater aquarium crabs are fine for reef tanks and which ones would be reef destroyers. Sorry to be so harsh, but I almost made the same mistake, and I know how important my tank is and how hard it is to get the right system setup and stable. This hermit crab species grows up to 1 ½ inches and they are a great choice for tanks with small species of fish because they do not tend to bother other tank inhabitants like some hermit crabs do. Like you already have on your Crab info they help keep the tank clean. Crabs and crayfish: Crabs eat the snails! Saltwater Crabs are a must have cleaner for any reef aquarium. Please Please Please return this crab to the fish store you got it from, your tank is only 6 months old, and it could be very harmful to the sandbed you described in your tank specs. If you desire to keep large hermit crabs, do so only in a tank of suitable environment and size, and remember they will outgrow their shells. Setting up a tank for fiddler crabs is simple, but it’s not the same as setting up a fish tank. My Husband and I have a new saltwater tank that is about 2 months running. You can also treat them with steamed veggies but they should be cut into tiny bits. We had a few fish in it (Purple Tilefish, 2 clownfish, Emperor Angel, and a foxface), as well as hermit crabs and snails. Do not keep with fish that will harass or eat them, such as certain cichlids. Yes they will every once in a while catch a fish and eat it. Hermit crabs are actually social animals that live in colonies, and they are called hermit crabs because they protect their soft bodies by living in shells that other sea animals discard, or that they obtain by killing other sea animals. Most require live insects, worms, and/or small fish to eat. However, when they kill animals for their shells, hermit crabs usually do not eat the animals themselves. Best Fiddler Crab Tank Mates: What Fish Can Live with My Fiddler Crab? May catch and eat small fish, dwarf African frogs and other tank mates that live or sleep on the bottom of the tank. I have red clawed crabs in my tank. If we have a sea crab, a river or a hermit at home, it will be a bit complicated to give animal carcasses and other foods that I would choose in their habitat.