freshwater crabs care guide header

Freshwater crabs are a fun, unusual pet to keep in your aquarium. Some are fully aquatic – meaning they can live in standard aquariums – while others are more half in-half out of water species.

They can grow, generally, anywhere between one and four inches across, are omnivores, and generally like their freshwater fish tanks with 72 to 82 degrees Fahrenheit.

Many of these freshwater crab tank dwellers make for great mini crab pets. The little one-inchers are ridiculously adorable, spunky, and rather comical at times. Other freshwater aquarium crabs also add color and comedy to the overall views of your aquarium.

Quick Intro to Freshwater Crabs

Before we dive into specific species care notes, let’s take a look at some general information.

First off, let’s look at what crabs eat.

This important topic revolves around their omnivorous nature. They will eat smaller crustaceans and fish, insects, and larvae, as well as plant matter. Some will also nosh on some algae, as well.

They do best with freeze-dried foods, frozen foods, and low-grain or no-grain pellets and flakes as well. The freshwater crabs for fish tank will eat blanched peas, blanched zucchini, and algae wafers, as well.

Be sure to give them a solid balance of these types of food for their optimal health. Just remember to give them food that will sink to the bottom of the tank – or the other critters in there will beat them to it. Also, thaw out any frozen food before feeding that to them.

Some freshwater crabs may eat snails, so be careful with how you house these guys. Some species of freshwater crabs are cool with these and tankmates and will leave them be. Others think “delicious snack” when they see them.

Next, let’s look at basic water conditions, tank size, et cetera.

Fresh water crabs aquarium requirements generally need to be at least 5 gallons in size, with water somewhere between 72 and 82 degrees Fahrenheit. It’s also important to provide most of them rocks that are outside the water. Most crabs are not fully aquatic – though you’ll see some exceptions that are – so that non-watery surface is necessary.

Freshwater crabs also need plenty of décor. They’re climbers and hiders by nature, which means they need rocks, plants, caves, sunken ships, treated seashells and treated driftwood, and other objects that they can climb across and hide among.

Next, let’s look a little at their behavior.

Freshwater crabs are scavengers – meaning they scrounge around for leftover food and debris that they can claim for themselves. They’re also heavily nocturnal, so they’ll do this scavenging at night, when they’re most active.

Crabs climb everything – and can climb just about any kind of surface they’ll find. Airline tubing, intake tubes, rocks, driftwood, posts – anything there will be climbed. Because of this, you’ll need to make sure you keep a secure lid on the fish tank they live in and patch any holes that might come up over time.

Also, all crabs molt, so if you notice your crab is lying on his back, he may be molting. Keep a close eye on him if he’s like this to verify that’s what’s going on.

Many freshwater crabs also benefit from a little freshwater salt, as well, so grab some from your pet store or online and follow the instructions included.

As to daily care, keep these things in mind.

  • Daily check their filter, water temperature, and verify equipment is running properly.
  • Weekly check the water quality.
  • Monthly change 10 to 25 % of the total water volume every 2 to 4 weeks.
  • Slowly introduce new inhabitants, décor, and plants to the aquarium, rather than all at once. Quarantine any new animals or fish before introduction to reduce potential disease outbreaks.

Finally, a health care note: Medications containing copper are toxic to your crabby pals. Avoid these at all costs.

Types of Freshwater Crabs That Make Great Pets

There are loads of viable pet crab species that will do well as fish tank crabs. You’ve got everything from Vampire Crabs to Panther Crabs, freshwater Hermit Crabs to Thai Devil Crabs, and several others that are colorful, spunky, and fun to watch and care for.

Let’s take a look at some of these awesome pet crabs.

1. Freshwater Pom Pom Crabs

boxer crab pom pom crab
By prilfish from Vienna, Austria – Boxer Crab carrying eggs – Lybia tessellata, CC BY 2.0
Scientific NameLybia edmondsoni
Other NamesBoxer crab
Care LevelEasy
Natural HabitatEndemic to Hawaii
Aquarium Conditions72-78° F, dKH 8-12, pH 8.1-8.4, sg 1.020-1.025

Basics on freshwater pom pom crab care are easy. They have pretty wide parameters – apart from that temperature, and are pretty easy-going, peaceful crabs. 

In fact, they’re much less aggressive than many other freshwater crabs, so they make for a really great pet crab. This might seem counterintuitive since they are called boxer crabs and hold stinging anemones in their claws!

Pom poms are fully aquatic, so they do well in aquariums with other aquatic critters, as long as the others aren’t aggressive towards crustaceans. 

Some good tankmates for Pom poms include clownfish, Gobies, Blenies, cleaner shrimp, leopard wrasse, and other non-aggressive freshwater fish and invertebrates.

Where to Buy Pom Pom Crabs

2. Freshwater Fiddler Crab

fidler crab
Scientific NameUca
Other NamesCalling crab, mini crab
Care LevelEasy
Natural HabitatSalt marshes, beaches, mangroves of West Africa, Western Atlantic, Indo-Pacific, and Eastern Pacific regions
Aquarium Conditions74-84° F, KH 12-30, pH 8.0-8.2

Fiddler crabs are technically brackish water crabs, rather than freshwater crabs, though many folks have tried keeping them in freshwater only environs. Part of the misunderstanding may be due to the fact that there are over 100 species of fiddler crabs in the Uca genus.

These guys are easy to identify thanks to the asymmetrical claws they have. Males have one claw that is much larger than the other claw, though female mini crabs have equally sized claws.

Fiddler crabs are semi-aquatic crustaceans that are a fairly hardy species, so Fiddler Crab care is considered one of the easiest options for newbies. They do best in brackish water aquariums and must have plenty of out of water surfaces to climb over, since they are not fully aquatic.

Provide them with plenty of driftwood – unbleached but clean is fine – rocks, and other places to scramble and hide both in and out of the water. For the best freshwater fiddler crab care, give them places for burrowing, as well, as they love digging into the sand.

Where to Buy Freshwater Fiddler Crabs

3. Vampire Crabs

little red vampire crab
Scientific NameGeosesarma aurantium
Other NamesDevil crabs, red devil crabs, carnival crabs
Care LevelEasy to intermediate
Natural HabitatIndia, Southeast Asia, Solomon Islands, Hawaii, Java, Krakatau or Riau Islands
Aquarium Conditions75 – 82 F, 7.5 – 8.5 pH, 0 – 10 KH, 4 – 16 GH

Vampire crabs are a colorful, unique addition to any home. They lead plenty of rocks, wood, and other objects to climb on and sit on, plus they love Java Moss, sandy substrate, and fellow Vampire crabs to keep themselves company.

In their tank, they need about 50% land and 50% freshwater meeting their pH and hardness, et cetera, parameters. You can house several in a fairly small space – 10 to 20 gallons works for up to 6 of these guys! – because they are non-aggressive, social animals. They work well with larger snails and some shrimp as tankmates, too.

Vampire crabs eat the standard crab food choices, but they also love small crickets.

Where to Buy Vampire Crabs

4. Gold Claw Crabs

two gold claw crabs
Scientific NameUca
Other NamesYellow claw crab
Care LevelEasy
Natural HabitatSalt marshes, beaches, mangroves of West Africa, Western Atlantic, Indo-Pacific, and Eastern Pacific regions
Aquarium Conditions74-84° F, KH 12-30, pH 8.0-8.2

Gold claw crabs are a type of Fiddler Crab. We’re distinguishing them from the rest, however, because of the unique looks they offer and the slight behavior differences we’ve noted that not all Fiddlers display.

For example, many fiddler crabs are cool with plants. But Gold Claw crabs destroy them – or as some fish keepers have put it, they massacre live plants.

These fiddlers are named Gold Claw because the males have that asymmetrically larger claw that happens to be distinctly yellow, or golden, which is very differently colored than the rest of its body.

These crabs are scavengers at the bottom of the tank. They dig and burrow at times and that means this particular fiddler crab species needs sand substrate, not rock, pebbles, gravel, or other forms.

Gold claw crabs are also especially good at giving Houdini a run for his money. They’re excellent climbers and exceedingly cunning and crafty – so they’ll find their way out of anything. Be absolutely certain you secure the lid on their aquarium every time you touch it.

Where to Buy Gold Claw Crabs

5. Thai Devil Crabs

thai devil crab in fish tank
User breelle at Aquarium Advice
Scientific NameClariosoma Camifax
Other NamesBlack devil crab, Soapdish crab, Rainbow crab, Purple Thai Devil crab
Care LevelEasy
Natural HabitatForests and rivers in Southeast Asia
Aquarium Conditions72–82 Fahrenheit

Another popular option is the Thai Devil Crab. The name is a misnomer, however. These guys are very gentle, non-aggressive little crabs that only grow to be about three inches across, max. They come in a variety of colors – including a vibrant purple – and are extremely active. So, they make great pets for a lot of reasons.

Thai Devil crabs do need lots of room at the bottom of their tanks. They’re scavengers, like most crabs, love to climb and roam, and generally just need lots of space for a happy life, thanks to their high activity levels.

They need lots of dry land to hang out on, since they’re not fully aquatic, and definitely need some sandy bottom to hide and dig around in.

These guys love dried algae in particular, along with fresh and dried fruits. You should also provide them with a moderate to heavily planted home, as they rely on the plants for both food and shelter.

Where to Thai Devil Crabs

Unfortunately, Thai Devil crabs are a bit more difficult to come by than many of these other freshwater crab pets. But you can find them online at

6. Panther Crabs

panther crab in aquarium
Scientific NameParathelphusa pantherina
Other NamesLeopard crab
Care LevelEasy
Natural HabitatLake Matano, Sulawesi, Indonesia
Aquarium Conditions59 – 86 F, 6.0 – 8.4 pH, KH: 5 to 8, GH: 4 to 6

Panther crabs, also sometimes called leopard crabs because of their coloring, are one of the most popular small crabs because they are easy to house with certain fish and add some color and intrigue to your freshwater aquarium.

You can keep these guys with tetras, mollies, bettas, catfish, and guppies. And though they’re primarily aquatic, if you have a tall enough tank that would allow for it, having some “dry land” for them to scramble onto sometimes is a good idea.

These little crabs are easy to sex. When you flip them over, females have a salmon-colored spot on their shell, with a “tip” at the top of the coloration. Males, however, have entirely white or ivory colored underbellies, along with some uniquely shaped lines that sort of look like a butterfly.

And though these are a larger crab species than many of the other freshwater guys we’ve talked about, they’re not particularly aggressive, which is why they work with many species of fish. Just don’t house them with slow movers or much smaller fish. And always keep them well fed to avoid aggressive or the eating of their tankmates.

The best panther crab care is going to involve keeping them in a colony of about five of them in a single fish tank together. The minimum for this many is about 15 gallons.

Where to Buy Panther Crabs

7. Freshwater Hermit Crabs

a hermit crab emerges from its shell
Scientific NameCoenobita
Other NamesHermie, Caribbean Hermit Crab
Care LevelEasy
Natural HabitatIndo-Pacific region, Atlantic Coast of the Americas, one species in the Pacific coast of the Americas, one species in West Africa
Aquarium Conditions72 to 82 degrees

These guys are technically terrestrial crabs, meaning they live on land, rather than in the water. There are a number of hermit crab types, but the one we’re looking at most closely is the Caribbean Hermit Crab. These guys are energetic, intriguing, and fun.

Freshwater hermit crab care is generally pretty easy. They are very social and friendly, intelligent, and have long lifespans, if well cared for.

Hermit crabs, despite their name, need to have other crabs around. They do best in pairs or groups and require plenty of space for roaming and exploring. For a pair, you should have a 10-gallon tank minimum. Avoid positioning their tank in direct sunlight, near windows, or any place else that might result in drastic temperature changes.

Give them plenty of sand – at least three times deeper than the tallest point of your hermie – to ensure they feel safe and secure in as natural an environment as possible.

Since they’re not aquatic crabs, they don’t need an aquatic environment. Instead, they need some water bowls positioned throughout their enclosure. The bowls should be large enough for them to submerge full, but not so large that they get trapped. Fill one bowl with fresh, purified water and fill the other with purified water with marine salt. You can also add a sea sponge to the dishes to help them get in and out safely.

Where to Buy Freshwater Hermit Crabs

You may be able to buy some freshwater hermit crabs online, but for the most part, you will need to go to a physical pet store to find a healthy hermie. A few places to try looking, both online and in person include:

Other Freshwater Crabs That Can Be Kept as Pets

There are a few other crabs you may consider keeping, though they’re not as commonly kept as pets. They still make great little tank buddies, add some spice to life, and are enjoyable to watch and even play with.

3 More Things to Know About Freshwater Crabs

  1. Hermit crabs are actually more closely related to porcelain crabs and squat lobsters than they are true crabs.
  2. The largest land invertebrate on the planet is the type of hermit crab that is called the coconut crab.
  3. There are about 1,300 species of freshwater crabs around the world, plus up to another 65% again of unidentified freshwater species.

About The Author

Leave a Comment

Your email address will not be published. Required fields are marked *