If you want to maintain reef tank then invertebrate like crab,shrimp and snails are the species that you should consider for your reef tank. Emerald crab is one of the best invertebrate you can keep while setting up reef tank. You can even place emerald crab in your saltwater tank if the tank-mates are not posing any threats to them. Emerald crab is usually found in Caribbean and Atlantic ocean.
As this crab is algae eater and removes many varieties of waste in the tank so it is preferred invertebrate choice of marine aquarist. You don’t need to care much about emerald crabs as they’ll take care of themselves in most of the situations.
You need at least 25 gallons of tank if you wish to maintain single emerald crab in your reef tank. If you want to keep more than one crab then consider getting larger tank. Small tank with multiple invertebrate could cause conflict so make sure you get larger tank when it comes to maintaining reef tank.
Size & Color: They grow up-to size of about 2 inches to 5 inches. They have shiny green color with slightly whitish shade if they’re juvenile. They also have hairy legs and are quite small as well.
Ph & Temperature: They don’t require much high temperature so you need to maintain at least 21°C – 27°C. Ph should be maintained at about 8.1 – 8.4 with carbonate hardness of about 8 – 12°dKH.
Breeding: Only veteran and aquarium shopkeeper can tell you the difference between male and female. There is not much of reports about breeding emerald crabs in home reef tank setup.
Food: Most of the time they prefer to eat algae. Also emerald crab is known for eating bubble algae & coralline algae keeping tank clean from algae. They also prefer to eat scavenge on the live rock and sand. If you want to vary their diet then add scavenge aquarium foods pack into the tank regularly.
Behavior : They usually wander across the tank for food and often rest on live rock or hide under stone/marble cave. If placed with more than one emerald crab then they appear semi-aggressive. If placed with snails in reef tank then they may attack if they’re mature. So place in the tank with other invertebrate which pose no threat or are their diet. You need to do bit more research for tank-mates if you want to keep them in the reef tank. Other than that they’re peaceful and form no threat to other peaceful reef tank fishes. Avoid keeping them with snowflake moray eels.
They’re quite cheap in comparison to other crabs and costs 7$-18$ in most of the aquarium shops. They’re also available online but you need to check what you get when you order them online. Emerald crab is perfect invertebrate if you wish to maintain large reef tank. As they require less care and moderation so they are like set and forget type of invertebrate for your reef tank.