Emerald Crab

All You Need to Know About the Emerald Crab

The Emerald Crab is known as Mithrax sculptus in the scientific realm, but is also frequently referred to as the Green Crab or Green Coral Crab by laymen. These relatively small saltwater invertebrates prefer the saltwater environment. Many people add these crabs to their saltwater tanks to assist with cleaning and algae reduction. Below you will find a complete examination of the Emerald Crab, specifically when they are kept in household aquariums.

First let’s delve into the physical appearance of these crabs. They tend to be green (hence their other common names) and rough in terms of their texture. This texture proves to be relatively useful in defending themselves in the wild. Their legs are relatively hairy with claws that are smooth to the touch. The crabs generally grow to be somewhere around one and a half inches long. Furthermore, one thing that is unique about these crabs (and that sets them apart from others) is their ability to survive in temperatures between fifty-five and ninety degrees Fahrenheit, unlike most water-based invertebrates.

When attempting to have any animal found in the wild live in a simulated environment, it is essential to understand how these creatures interact with their natural atmosphere. Therefore, we find it important to examine the Emerald Crab in their natural habitat. Most of these crabs tend to hide during the daylight hours and become relatively active at night. Since they prefer to feed off algae, when they are active at night they leave their rubble hideout and seek out any algae in the surrounding area. As a result of their algae consumption, they are generally found in many household saltwater aquariums to assist with keeping the tank clean.

Anyone who has had a freshwater or saltwater fish tank is likely to understand the effects of algae without a species within the tank that feeds off these algae; having an excess can cause your fish to become sick and die. Therefore, adding an Emerald Crab to your saltwater tank can drastically cut down on the unwanted algae. You will need one of these crabs per twenty-five gallons. One crab will not be able to successfully clean a tank larger than twenty-five gallons and having more than one crab in anything smaller than twenty gallons is highly discouraged. Having more than one crab in this close of a proximity may result in aggressive behaviors. Furthermore, some of these crabs are known for being aggressive toward snails; therefore, it may be recommended that you have one or the other.

This crab is compatible with reef tanks but should be monitored for aggressiveness with other species (especially crabs and snails). Be sure to include sufficient hiding spots and gravel within your tank. As discussed above their hiding tendencies come from the wild and are something that makes them feel more comfortable in a simulated environment. It is also recommended that you only house these crabs in tanks that are at least ten gallons for best results. Be sure to monitor the level of algae in the tank—if there is not a decent amount supplements may be required to help feed your crab.

In conclusion, the Emerald Crab makes a great addition to your saltwater tank and proves to be easy to maintain. These crabs will consume the algae in your tank making it clean and safe for other species; however, do not completely rely on your crabs for cleaning purposes. Although they tend to do well with other species, be sure to monitor aggressiveness with snails and other crabs. In the end, these crabs are great for any aquarium over ten gallons as long as gravel and hiding places are incorporated to replicate their natural habitat.