Freshwater aquarium crabs can be kept as both individual pets in an aquarium or as part of an aquarium community. Crabs improve the water quality by consuming dead and dying matter such as leftover fish food and decaying plants. Crabs are also kept because of their attractive appearance and oftentimes quirky behaviour.
Mini crabs---also called fiddler crabs---are known for their antics and ease of care. The website "Live Aquaria" states that this semiaquatic species is commonly found in Florida, especially in swamps and lagoons. Mini crabs prefer residing in rocks, driftwood and other decorations that offer them places to hide and climb. Good water quality is important for the health of mini crabs, therefore aquariums with internal filters are recommended.
Freshwater Red-Clawed Crabs
According to the website "Wrong Crowd,", freshwater red-clawed crabs are natives of Asia and are predominant in the waters of Thailand, Hong Kong and Singapore. As scavengers they feed on decaying material and are not fussy when it comes to food. These crabs can live up to four years and prefer hiding under rock, wood or ceramic ornaments in an aquarium. Freshwater red-clawed crabs are more active at night. Aquariums need to be carefully sealed as these crabs are notorious escape artists.
Gold Claw Crabs
Gold claw crabs also originate from Thailand, Singapore and Hong Kong. These crabs can live up to two years as long as the water is clean and they have enough dead or decaying material to feed on. Gold claw crabs have one front claw that is larger than the other. Females and males of this species of crab wave this claw at one another in communication and mating rituals. The website "Aqualand Pets Plus" states that males and females can be distinguished by the white-edged claw the male crab sports.
Soap Dish Crabs
Soap dish crabs are less friendly than other types of aquarium crabs. They are even shipped in soap dish containers (thus explaining the name) separately to prevent them from killing one another. These crabs' diets are not as simple as others as they will eat fish and anything that comes close to them---even if it's another soap dish crab. Despite their aggressive behaviour, they are prized pets because of their attractive red, yellow, orange and purple shells.