The crab will carry on molting and growing until it is unfavorable to do so. At unfavorable conditions (during times of environmental stress) the X-organ will secrete the molting inhibiting hormone, and the molting process will cease.

Crabs and other crustaceans (lobsters, shrimps, prawns etc) have a hard shell or exoskeleton. The old shell splits open and the crab climbs out. It quickly pumps up its body by drinking lots of water before it sets hard. It can then grow into its new shell until it needs to make a bigger one all over again.

Crabs have a hard exoskeleton (commonly called a shell) that surrounds the outside of their bodies. This hard shell cannot expand as the crab grows, so periodically the crab must shed its shell and develop a new and bigger shell in a process called molting.

During the first two years, crabs shed their shell several times a year, increasing in size with every successive molt. At a size of about 4″ molting becomes less frequent and occurs only once year.

If your hermit crab isn’t moving around much, the water in its habitat or even toxic paint on its shell could be killing it. Lethargy can also be a sign of stress. Recognize that most hermit crabs like to play and will move around their habitats a lot if they are not molting or sick.

Determine whether your crab is molting. Your crab may be molting if it is out of its shell and not moving. If there is no fishy smell, there’s a good chance that your crab is molting. Molting usually lasts about two weeks, so you may need to wait some time before you are absolutely sure.

Although they have gills, Fiddler crabs can drown if there is too much water. They retreat to their 12″ burrows in the sand at high tide and seal the burrow with mud or sand.

Most problems result from improper salinity, pH or temperature or too many crabs in a limited area. Crabs also die if they were kept in fresh water at the pet store. Calcium and Iodine are required for molting.

Fiddler crabs should not break the skin if they pinch you, but they can give a sharp pinch with their claws. They should be handled as little as possible, and you should wear gloves when you do handle them.

Most aquarium crabs are not 100% aquatic, so they need a bit of dry land in their tank.

However, unlike fish, blue crabs can survive out of water for long periods of time-even over 24 hours-as long as their gills are kept moist. When out of water, crabs will seek out dark, cool, moist places to help prevent their gills from drying out and to hide from predators.

Aquarium crabs are another interesting invertebrate. They are more predatory than shrimp, however, so choose only smaller crabs for a guppy aquarium. Fortunately, guppies are tolerant of some salt in their water. With these consideration in mind, you can keep guppies and crabs together.

Always keep more shrimp than guppies to give the shrimp a better chance of survival. Adult guppies will eat both adult and baby shrimp. Even guppy fry will eat small shrimp that fits their mouth.

In simple terms, guppies eat shrimp including the cherry shrimp species. That is why you will have to take a few precautions in order to ensure that both can coexist.