We often picture crabs as saltwater creatures that scuttle along the seashore. However, this world also houses some beautiful freshwater crabs for aquarium that can make the perfect addition to your aquarium. These scavengers add a completely different dynamic to your tank, and are very entertaining to watch as they scurry around and grab whatever they can get their claws on.
Freshwater crabs are usually very small, making them perfect for almost all tank sizes. They also help keep aquariums clean, so you don’t have to worry as much about a dirty tank.
Keep reading to find out more about freshwater crabs and how you can add them to your tank!
1. Fiddler Crab
Although fiddler crabs are cute creatures, they still pack a lot of personality in their tiny bodies. They only have a leg span of around 2 to 3 inches, and don’t grow very large at all.
Their most distinguishing feature is their large claw. Male fiddler crabs usually have one large claw, which they use to fight off and intimidate predators. They also use the claw for mating purposes. Interestingly, fiddler crabs are not completely aquatic, and spend their time both underwater and on land. These crustaceans also have primitive lungs and gills to support their adventurous lifestyle.
Fiddler crabs need brackish water to stay happy and healthy. Make sure the water in your tank has a salinity between 1.001 and 1.008, and a temperature between 75- and 86-degrees Fahrenheit. The pH balance should also be a bit alkaline, measuring somewhere between 8.0 and 8.3.
2. Thai Devil Crab
Contrary to their name, Thai Devil crabs are sweet little creatures. They usually have a bright purple body, but they also come in shades of glowing oranges and reds. All these vivid colors give these crustaceans a unique, exotic edge, while the contrasting red color on their claws and heads makes them stand out from other crabs.
Thai Devil crabs boast antennae-like eyes that look a bit aggressive but don’t judge these creatures by their looks. They have a very peaceful nature, and only get aggressive when they’re messed with. Like most other freshwater crabs, they also need a dry, sandy area with no water to stay healthy.
These crustaceans are omnivores that eat aquarium algae, plant detritus, and protein-based snacks. They also enjoy brine shrimp, and will even eat any leftover pellets that sink to the bottom of the aquarium.
Make sure you have hiding spaces in your tank before you get these crabs. This is because they thrive best when they have small caves to hide in, or soft sand to burrow into for safety.
3. Vampire Crab
Vampire Crabs get their name from their glowing, vampire-like eyes, white splotches, unique deep purple coat, and beautiful pink claws. They’re largely nocturnal and spend most of their daylight hours hiding. They’re quite aggressive as well, so it’s better to keep them in a single-species aquarium.
These crustaceans need lush environments and access to both water and land. Make sure that both areas are covered by plants because, along with feeding on plant matter, these crabs need vegetation for cover as well.
Vampire crabs are incredibly hardy creatures, and can adapt to a wide range of water conditions. However, they thrive in humid conditions and in temperatures between 82- and 70-degrees Fahrenheit.
It’s better to avoid pairing vampire crabs with large fish that might view them as prey. You can add shrimps, snails, and their own species to the tank, but make sure you have one vampire crab male to a couple of females.
4. Red Claw Crab
Red claw crabs are one of the most popular and readily available freshwater crabs for aquariums. They might be a bit skittish and shy in the beginning, but these crustaceans will eventually come out of hiding and start exploring the tank once they get comfortable.
These crabs are found in Asia, and usually reside in rivers that flow into the ocean. These natural water conditions mean they need brackish water with a temperature between 70- to 88-degrees Fahrenheit, and a specific gravity of approximately 1.005 to stay happy and healthy.
Like most other crabs, red claw crabs also prefer a lot of hiding places. However, try to avoid adding too many plants into the tank, as these crabs have a reputation for uprooting and shredding plant leaves.
As the name suggests, their powerful and sharp claws sport a bright red color and are capable of doing serious damage. Although red claw crabs live peacefully with other species, they do eat some fish, so try to avoid adding fish to the same aquarium as these crustaceans.
5. Panther Crab
Unlike other crabs, panther crabs spend most of their time underwater. They’ll still need a small piece of land to scuttle around every once in a while, but they mostly follow an aquatic lifestyle.
These crustaceans get their name from their unique orange coat and black spots. They’re also a bit aggressive, further making them similar to the temperamental wild cats they’re named after.
Panther crabs are incredibly hardy and adapt well to a wide range of habitats. That being said, it’s still advisable to keep them in temperatures between 75- and 82-degrees Fahrenheit so they stay healthy and happy.
Like fiddler crabs, a single large claw is also a distinguishing feature of male panther crabs. Females can also have one large claw, but they’re usually not as big as their male counterparts.
These crustaceans have a very aggressive nature, and should not be kept in groups. You can keep them in pairs, but make sure you keep an eye on them at all times.
6. Freshwater Pom Pom Crab
Pom pom crabs are still quite rare, so it can be a bit difficult to get them for your aquarium. But, if you manage to acquire one, you’ll have a lot of fun taking care of them.
Freshwater pom pom crabs stand out from other crustaceans because of their looks. These small creatures are approximately one-inch wide in the beginning and don’t grow any bigger than 1.7 inches.
The small patches of hair on their claws further make them look like cheerleaders waving around their pom-poms. These hairs are actually vital to their health and enable them to collect food, making it easier for them to feast on a bit of alga.
Freshwater pom pom crabs are fully aquatic. Since they spend all their time underwater, you won’t need to build any sandy areas up in your aquarium. That being said, it’s still advisable to keep the water levels low, as these crustaceans are excellent escape artists.
Lastly, these creatures thrive in temperatures between 78- and 68-degrees Fahrenheit and in a water pH balance of approximately 6.2 to 7.2.
7. Thai Micro Crab
Thai Micro Crabs are the perfect species for people who don’t have the room for a large tank. They only grow up to 0.4 inches wide, making them one of the smallest freshwater crabs for aquariums.
Their tiny size, coupled with their camouflaging grayish-brown color, makes these species difficult to spot. They’re also very shy and like to keep to themselves. They usually hide in caves and behind plants, and love scavenging for treats.
You can keep these crustaceans in aquariums as small as five gallons. It’s advisable to pair them in groups of five, and add small shrimp and other non-violent invertebrates to the tank as well.
As for their diet, Thai Micro Crabs are omnivores. Their legs are covered with tiny hairs that enable them to capture food particles and other microorganisms floating around in the tank. These crustaceans might also feed on insect larvae and algae.
8. Matano Crab
Residing in Lake Matano in Indonesia, Matano crabs are low-maintenance pets that boast a vivid appearance. They are large creatures, measuring around 3 to 5 inches wide with their leg span. These crustaceans have a bright purple body, and the joints near their legs are usually white, making them stand out from other species in the aquarium.
The best thing about these crabs is that they’re completely aquatic and spend their entire lives underwater. That being said, they are curious creatures that don’t mind a bit of land exploration. You can provide a small portion of land to keep them happy, but it’s not really necessary.
Matano crabs prefer water temperatures between 86- and 77-degrees Fahrenheit and a pH balance of around 7.8 to 8.2. They also have a slightly aggressive nature, so keep a close eye when placing them with fish and snails. They’re nocturnal as well, so you’ll probably find them scuttling about at night.
These creatures are excellent escape artists. Make sure you keep the aquarium sealed shut at all times, as they’ll jump at every opportunity to escape. Since Matano crabs are scavengers, they’ll eat almost anything, including dead organic matter such as fish.
9. Rainbow Land Crab
Rainbow land crabs are giants compared to most other freshwater crabs for aquariums. Measuring approximately 6 to 8 inches wide, they need a large amount of space. They’re also scavengers, so it’s better to opt for a large aquarium to keep them happy and healthy.
Rainbow land crabs are truly stunning with their distinctive eyes and bright colors. Their purplish bodies sport hints of vivid blue, while their legs range from orange to red.
These crustaceans spend a lot of time on land, so make sure your aquarium has a large land portion before you introduce them to their new home. If you don’t find them in your tank, don’t worry, as they spend a lot of their time burrowing in the sand.
These crabs are very easy to feed. They usually scavenge for plant matter, but they will eat almost anything, including bloodworms, fruits, pellets, and fish meat.
Rainbow land crabs are aggressive and might even kill their own species. They’re not very sociable, so it’s best to keep them in a separate tank.
Tips for caring for a freshwater crab
While you can follow some general care guidelines for freshwater crabs for aquariums, it’s important to remember that every species is different. Make sure you do a bit of additional research about your specific species before you add them to your tank.
Although it may seem intimidating, caring for a freshwater crab is not that difficult. In fact, it’s easier to take care of these crustaceans than many other types of fish.
Setting up the right habitat
It’s important to set up a healthy and comfortable living space for your new pet before you bring it home.
First, find a suitable tank. While you can go for an aquarium as small as 5 gallons, it’s better to opt for the biggest aquarium that you can fit in the available space. This way, your freshwater crabs won’t feel cramped as they grow, and you’ll be able to add more tank mates as friends in the future.
Most freshwater crabs are not fully aquatic, and do require a bit of dry land. Generally, a good ratio is two-parts water and one-part land, but this can vary according to species. You can create a dry area in your aquarium with rocks and sand, or you can just pour sand into one corner of the tank and pile it high to build a small beach for your small friend. You can also buy ready-made land setups online or from pet stores.
Keep in mind that if you plan to add only freshwater Pom Pom crabs, or any other fully aquatic crustaceans to your tank, you don’t need to build a dry area in your aquarium.
The location of your tank is extremely important, as direct sunlight can be harmful to freshwater crabs. Place your aquarium in a warm area, build a dry area for your crabs, and then fill the aquarium with water. Wait for the sand to settle in the water before placing your crabs inside. Instead of adding water directly into the tank, you can also fill a large container with water and place it in the tank’s lower section for easier cleaning and maintenance.
It’s essential that you only use filtered water, as tap water generally contains chlorine, which can be extremely dangerous for crabs.
Crabs prefer warmer water with a temperature between 72- and 82-degrees Fahrenheit. You can easily use an aquarium thermometer to monitor the temperature of your tank. It’s also advisable to ask the pet store or the breeder for specific temperature requirements before you purchase the crab, as some crustaceans are hardier and more adaptable to different temperatures than others.
Crabs love to explore and climb, so it’s important that you indulge their curious nature by filling your tank with objects to play with. You can add sticks and stones, or purchase colorful, ready-made decorations from pet stores and pet supply websites. You can also place a few sections of cleaned-up piping in the tank, so your crabs have something to crawl on or hide inside. Just make sure that the objects don’t have any sharp edges that could hurt the crustaceans.
Introducing freshwater crabs to the aquarium
Following are some tips you can follow to gently introduce your freshwater crabs to your aquarium:
- It’s better to set up the tank before you purchase freshwater crabs for aquariums. If you bring the crabs home before the aquarium is complete, then make sure you don’t leave them in the packaging container. Instead, create a temporary tank for the crustaceans by filling a plastic bin or bucket with filtered water.
- Keep a close eye on your crabs, and don’t let them escape. These tiny creatures can be incredibly difficult to find if they manage to hide and skip your notice. If you do lose your crab, try to find it as quickly as possible, as they won’t survive long outside their habitat.
- If you add more than one crab to your aquarium, observe their behavior to see whether they get too aggressive or territorial with each other. If they don’t behave, you might have to move one to a different tank.
- Most freshwater crabs have a non-aggressive nature, and you can easily place them with other peaceful crustaceans and fish. Small freshwater shrimp are usually good tank mates for freshwater aquarium crabs. Just avoid adding aggressive fish, such as cichlids, to the same aquarium as your crabs.
Feeding freshwater crabs for aquariums
Freshwater crabs love to eat both animal and plant matter, and will chomp down whatever organic matter they’re able to get their claws on. You can also supplement their diet by feeding them store-bought food. Some of the most common crab foods include:
- Cooked zucchini squash
- Crab food formulas
- Algae wafers
- Brine shrimp
- Cooked peas
- Small pieces of fish
It’s also advisable to use a calcium supplement, as freshwater crabs need calcium to molt and develop healthy new exoskeletons.
You should also keep an eye on which foods your crabs like to eat and which they don’t. Also, remember to remove any old food that’s been floating around in the aquarium for more than a few days. Hungry freshwater crabs might also gobble down rotten food, which can be damaging to their health.
When you feed your crabs, start by adding just a bit of food and then increase the amount as needed. Giving too much food to your pet can result in potentially unhealthy conditions and can also make the tank smell and look bad, making cleaning a real hassle.
Maintaining the aquarium
Remember to keep your aquarium clean and healthy by regularly changing the water. Whenever the water smells or looks dirty, replace it with fresh, filtered water as soon as possible. Make sure you also get rid of dirty sand and add a new pile as needed.
Like all other crustaceans, freshwater aquarium crabs also shed their exoskeleton. The molting process replaces the old layer with a new one, so don’t worry if your crab starts acting weird as this is a natural, necessary, and normal process.
You should leave molting crabs alone as much as you can. During the process, your crab will withdraw into its own world and will not socialize with you or any of its tank mates. Once the molting process is complete, your little friend will return to its sociable self. Remember to avoid touching your crab during the molting process, and never try to pick at or peel its shedding skin.
Also, don’t be worried or grossed out if your crab starts eating its shed exoskeleton, as this helps them get the needed vital calcium they need.
Will freshwater crabs eat shrimp?
The answer to this question depends on the species of the freshwater crab. Some crabs are herbivores and do not eat shrimp, while others, like vampire crabs, will eat anything from vegetation to commercial crab pellets and live insects.
What crabs clean fish tanks?
Hermit crabs are usually one of the first creatures that aquarists add to their aquariums, because they’re excellent at controlling common algae problems.
What fish can live with freshwater crabs?
Most freshwater crabs for aquariums have a non-aggressive nature and can live peacefully with other crustaceans and fish. Small freshwater shrimp are usually good tank mates for your aquarium crabs, for example. Just don’t add any aggressive fish, such as cichlids, to the same tank as your crabs.
Are crabs easy to take care of?
Although freshwater crabs have a tough exoskeleton, they’re incredibly fragile pets. However, you can easily keep them healthy and happy by just setting up a nice habitat for them and feeding them properly.
How big do freshwater crabs get?
Adult freshwater crabs for aquariums can often grow up to 1 to 4 inches across. However, the exact size differs with the species.
Although freshwater crabs are not high-maintenance pets, you will still need to spend time and money to ensure your pets have everything they need to live their best and most comfortable life. In return, you will get an entertaining little friend who will definitely be worth the trouble.
Hi, my name is Adam and I’m an aquarium enthusiast! I didn’t discover the joys of being an ‘aquarium fanatic’ (as some of my friends call me!) until I was in my 20’s. When I first started out I found it difficult to find all the information I needed so I started this website to compile all the useful information I can think of. Enjoy!