If you have a freshwater aquarium, you should know that you don’t have to limit yourself to only raising fish. There are tons of fun species you can keep in a fish tank – and they don’t have to be just fish.
From shrimp to snails and even frogs, there are plenty of other options. One option you need to consider? The freshwater crab. Many people assume that crabs only live in a saltwater environment, but that is simply not the case. There are dozens of types of crabs that are well-suited to life in a freshwater or brackish tank.
Freshwater crabs tend to be a bit on the small side. This is why many aquarium hobbyists refer to these species as “miniature crabs.”
No matter what kind of crab you choose for your aquarium, the most important thing for you to know is that these creatures are scavengers. They will spend much of their day ambling around the tank, searching for loose scraps of food to clean up in the tank.
As a result, these creatures aren’t just fun to watch – but they also serve a useful, beneficial purpose, too. They can help keep your tank clean, working on their own to tidy things up or even alongside other algae eaters, like bottom-feeding fish and snails.
Many people avoid keeping crabs in their freshwater tanks because they don’t think that they have the skills or knowledge necessary to raise them. That is simply not the case! Caring for crabs is often easier than caring for fish. Here’s what you need to know.
First, you need to make sure you have an appropriate tank. The smallest aquarium you should use is five gallons – an aquarium that is ten gallons or more will be ideal. You should purchase the largest possible thank for your available space and budget. This way, you won’t have to crowd your crabs as they grow. You can also have enough room left over for adidtional tankmates. After all, it’s no fun to just have one crab in a small aquarium!
You should also know that while aquarium crabs thrive in an aquatic environment, they are not fully suited to a 100% aquatic landscape. Therefore, you will need to give them a bit of dry land. You can purchase a ready-made tank or even set up a paludarium. A good rule of thumb to remember is that you should have two parts water to one part land. This ratio may vary depending on the species, but usually, you can use the rocks, sand and other items you might find at the aquarium store to establish a suitable area for your crabs.
Looking for an easy way to set up your tank for your new clawed inhabitants? Simply pile sand in the tank to create a nice little beach for your creature. You can also purchase a tank that is already pre-filled with a land area to provide a habitat for your crabs.
If designing an aquarium with a bit of land space doesn’t seem to be the right choice for you, for whatever reason, you can also purchase crabs that are designed to live in a fully aquatic environment – an example of such a creature is the Freshwater Pom Pom crab.
Ideal Tank Environment For Crabs
When you are setting up your tank for your crabs, you must make sure you select an area that does not receive direct sunlight, yet is adequate warm. Too much sun can harm the health of your aquarium crabs. After creating your dry areas, fill the aquatic section with water. If it becomes cloudy after you’ve filled the tank, give it some time to settle back down.
Only use water that has been filtered. Tap water contains chlorine, which can not only make your crabs very ill, but kill them. Crabs prefer water that is somewhat warm, ideally in the range of 72- and 82-degrees Fahrenheit. You can measure the warmth of your tank by inserting an aquarium thermometer in the tank. Often, allowing your water to sit at room temperature for a few days before filling the tank will be enough to get it to the optimal temperature.
This temperature range varies depending on the type of crab that you have. While some are more adaptable to a range of conditions, others are very particular about their needs. If your aquarium tends to run cold, make sure you purchase a heater to keep your crabs at the ideal temperature.
And remember, if the type of crab you selected prefers a brackish environment, you may need to add a bit of marine salt to your tank. Make sure you read the directions on the package carefully to get your ratios right, and always ensure that the other inhabitants of your tank (like fish) can tolerate a brackish setting.
Crabs don’t need a lot to be happy in the tank, but you should give them plenty of things to explore by adding decorations like rocks and sticks. You can even buy decorations from pet stores that are designed specifically for crabs. Just be vigilant to make sure there are no sharp edges in the tank.
Keep your tank nice and clean. You should perform regular water changes and make sure you get rid of water any time it looks dirty. Watch your crabs for signs of illness such as lethargy, decreased appetite, or slow movement. You should also know that crabs shed their exoskeleton as they grow – this is a natural behavior and is marked by cloudy eyes, a faded exoskeleton, and digging behavior.
You don’t need to worry about your crab molting. This is something to be expected. However, you can make the transition easier for your crush by providing a clean tank environment and making sure you don’t house your freshwater crab with aggressive tank mates who will damage the fragile crab while it is transitioning to a new shell.
Once you have your tank set up, you are ready to go! Want to learn about the best types of freshwater crabs? These are some of the most popular – and enjoyable! – freshwater crabs you can raise in your freshwater aquarium.
1 Red Claw Crab
These freshwater crabs are some of the most popular species you can raise in a freshwater aquarium. One of the more readily available options, red claw crabs grow to about three or four inches in length. When properly cared for, they can live for five years or more!
These crabs get their names from their signature bright-red claws. They tend to live in brackish water in the wild, but you can also keep them in freshwater – this is a common practice among pet stores and breeders. The best environment, however, will of course be a brackish water habitat.
Red Claws are climbers, like all other crabs, but these crabs are particularly good at doing so. You will want to make sure you include a lid on your tank, or else you may find these little space artists on the wrong side of the tank walls. They will also appreciate lots of decorations so that they can spend time scaling rocks and exploring your other tank decor.
2 Vampire Crab
Vampire crabs are quite spooky to look at – they have glowing eyes that stand out sharply against their purple, red, or orange bodies. These eyes are bright yellow. While vampire crabs are exceptionally rare – more difficult to find than other species of crabs for sure – they are so fun to look at that the additional search will be well worth your time.
These crabs only grow to about an inch wide. When cared for properly, they can live for three years or so in captivity. They need a very specific habitat, as they are not completely aquatic. You will need to provide them with more dry land than you do water.
Otherwise, vampire crabs are easy to care for. They will eat a wide variety of plant and animal foods – as long as you give them plenty of variety, you should do just fine.
3 Fiddler Crab
Fiddler crabs are extremely small, rarely growing larger than two inches. A striking crab to look at, this crab has one claw that is proportionate in size to the crab’s body. It will be delicate and rather small. The other claw is much larger than the other, and it’s often a bright-colored feature. This oversized claw is usually gold or yellow.
These crabs do not tend to be aggressive. However, they like to travel in pairs or small groups, so it’s recommended that you purchase a couple at a time. They also love to hide, so hiding spots from plants and decorations are a must. They are so tiny that you will often have trouble finding them in your aquarium decorations – be careful trying to move these in order to clean the tank!
In the wild, fiddler crabs live long lives. However, in captivity, they usually only live for a couple of years or so. Fiddler Crab is a broad term that includes over 100 different species. It may be worth your time to do some research before bringing one of these crabs home so that you know exactly what kinds of conditions your specific breed of fiddler crab requires.
4 Freshwater Pom Pom Crab
These crabs are also somewhat rare, only having been bred for creativity within the last few years. However, they are quite prevalent in the wild, often found gripping anemones tightly. Because of this, they have the appearance of holding tiny pom poms – just like crustacean cheerleaders! After all, that is how this crab got its name.
These crabs are quite small and have very delicate exoskeletons. These crabs usually reach only an inch or so in adulthood, although they might rarely reach close to two inches. A completely aquatic species, they are one of the easiest freshwater crab species to care for.
5 Panther Crab
The panther crab is one of the larger species of freshwater crabs on our list. It can easily grow to over three inches wide at maturity. With the ability to live for five years in captivity, this crab is also one of the most long-lived. It is named for the jungle-like appearance of its shell, which is totally yellow with some brown or black spots.
This freshwater crab has a reputation for being somewhat territorial. These species often fight among themselves and will also go after your other tankmates. As a result, it is recommended that you select a male and female pair or a harem of carbs to avoid fighting among the males.
6 Thai Devil Crab
The Thai devil crab may sound like a demonic beast, but in reality, these crabs are quite angelic. A docile freshwater crab, this species is an excellent companion for the other peaceful species in your tank.
Usually measuring only about two or three inches in adulthood, Thai Devil Crabs can sometimes reach four or even five inches, too. They can be found in a wide variety of colors, including purple and deep red. Most can live for 15 years, but usually will live five to ten in captivity.
7 Thai Micro Crab
Also referred to as the False Spider Crab, this species only grows to about half an inch in diameter. Typically brown or gray, this crab looks just like an actual spider with its long, gangly legs. These legs are covered in tiny hairs, which help them gather their food.
As a result, Thai Micro Crabs are sensitive to changes in the environment. They also need to be housed with peaceful tankmates who will not engage in predatory behaviors. You can keep this crab with invertebrates or even small schooling fish.
Once you have picked out and brought home your crab, your next step is to introduce him to the tank. Make sure your tank is set up and ready to go before you bring your crab home. You don’t want your crab to have to wait around itn eh the concept store packaging while you scramble to set up your tank. If you have to make any last-minute adjustments, transfer your crab to a plastic bin filled with filtered water – make sure you add some marine salt if necessary, too.
You will need to keep a close eye on your crab while you are finishing up your aquarium, as they have a tendency to want to explore. If a crab gets out of sight, it will be really difficult for you to find him and he likely won’t survive long after you’ve lost him.
If you plan on adding more than one crab to your tank, make sure you watch them interact with each other for a while after you’ve brought them home. Be alert for signs of aggression, as you may need to move one of the crabs to another tank.
Once your crabs have settled into their new home, you can begin to feed them. This will help make them even more comfortable. Crabs like both animal and plant foods, and they’ll eat any loose matter they can find floating around in the tank. It is also wise to supplement their diets with some storebought food.
Aquarium crabs will eat a wide variety of foods, including flies, algae wafers, brine shrimp, seaweed, zucchini, peas, crab food formulas, and even small pieces of fish. Be wary of adding your crabs to tanks that include fish that are smaller than your crabs – they will even gobble them up, too!
Some good advice is to use a calcium supplement when feeding your crabs. This will help provide them with the nutrients needed to grow healthy, sturdy shells. When you feed your crabs, keep an eye on them to see how much they are eating. You should start off with small portions and then add more as you see fit. Otherwise, too much leftover food can cause odors and bacteria to develop in your tank.
Are Freshwater Crabs Suitable For My Aquarium?
If you already have an established aquarium in your home, a freshwater crab could be the perfect addition you have been looking for. In most cases, freshwater crabs are not aggressive and can easily be housed with other peaceful crustaceans and fish. Freshwater shrimp are good options, and the only fish you need to avoid are those that are more aggressive.
As always, make sure you consult your local pet store or breeder about which aquatic animals might be best for your specific tank. This will help you get the best idea as to whether a freshwater crab will be a good fit for your particular environment.
With all of these tips in mind, know that crabs are not high-maintenance pets. They are inexpensive to raise and will provide you with endless entertainment – they’re definitely worth the extra steps in setting up your tank!