If you are looking to adorn your terrarium, paludarium, or freshwater aquarium with some new and somewhat unorthodox pet to care for, the crabs might be your choice. They are fascinating creatures to watch and have lots of personalities.
However, before purchasing one for yourself, it would be better to do your homework so you will be able to properly determine whether crabs make good pets in your case or not.
For starters, there are a lot of terrestrial, semi-terrestrial, and fully aquatic crab species to choose from and I will discuss some of them extensively in this article. Keep reading for more information on crabs that you can keep as pets in your home, in addition to housing features and proper care tips.
Without further ado here are some of the advantages and disadvantages of choosing a crab for a pet:
Pros
Here are some of the advantages and disadvantages of choosing a crab for a pet:
1. Ease of care
One of the great things about most crab species is that they are easy to care for. They are pretty hardy animals and can withstand varied ranges of temperature and water parameters.
Nonetheless, it does not mean that you can absolutely neglect your tank.
While these decapods are not excessively demanding in their care, you should still have the same amount of dedication to caring for them as for any other pet.
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2. Easy to feed (Great scavengers)
Generally, almost all crab species are omnivorous and opportunistic feeders.
In aquariums, they often feed on decaying matter. These consist of decomposing (dead) animals and decaying plants which are easy to shred with their pincers.
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3. Size
There are about 50 crab species that are commonly traded in the aquarium hobby. Out of this number, I’d highlight the top 10 types of the most popular pet crabs that you can keep:
| Species | Size across the legs span |
| Thai Micro crab | up to 1 inch up (~2.5 cm) |
| Pom Pom crab | 1.5 – 2 inches (~4 – 5 cm) |
| Fiddler crab | 1.5 – 2 inches (~4 – 5 cm) |
| Red Devil crab | 2 – 3 inches (~5 – 7 cm) |
| Vampire crab | 2 – 3 inches (~5 – 7 cm) |
| Red claw crab | 3 – 4 inches (~7 – 10 cm) |
| Halloween Moon crabs | 3 – 4 inches (~7 – 10 cm) |
| Panther crab | 3 – 5 inches (~7 – 12 cm) |
| Matano crab | 3 – 5 inches (~7 – 12 cm) |
| Rainbow crab | 4 – 6 inches (~10 – 15 cm) |
| Red Mangrove crab | 4 – 5 inches (~10 – 12 cm) |
As we can see, generally, crabs are smaller than most fish species. The average size across the legs span is around 2 – 4 inches (5 – 10 cm) in length.
Since crabs are relatively small in size, they do not require big aquariums/paludarium to hold them. A 10-gallon tank (40 liters) can suit most species.
4. Lifespan
Depending on the species, crabs can live from 2 to 8 years or even more if appropriately cared for.
Having them as pets can be exciting but it is also one big responsibility. After all, some crabs can live for many years. Therefore, before anyone commits to the responsibility of owning a pet crab, they should understand that.
5. Can be Kept Alone
Many crab species require little to no socialization, so it will not be lonely if you only own one.
It should be empathized that even though some species can be peaceful among each other, it does not mean that they will tolerate crabs of a different kind.
For example, Geosesarma hagen (Red devil crab) is probably one of the most social crabs in the genus Geosesarma, and they can be easily kept in large groups. However, if you put Geosesarma Hagen (Red devil crab), Geosesarma krathing (Tangerine-head crab), and Geosesarma Dennerle (Vampire crab) together, they will fight more often.
| Species | Socialization |
| Thai Micro crab | Yes |
| Pom Pom crab | Yes |
| Fiddler crab | Yes (with their kind) |
| Red Devil crab | Yes (with their kind) |
| Vampire crab | Yes (with their kind) |
| Red claw crab | No |
| Halloween Moon crabs | No |
| Panther crab | No |
| Matano crab | No |
| Rainbow crab | No |
| Red Mangrove crab | No |
6. Personalities
Most crab species have distinct personalities and exhibit fascinating behaviors that can make them wonderful pets. They are very exciting to observe.
One crab more ‘crabby’ than another, you know. Some crabs are generally bold, while others are shyer.
Friendliness, aggressiveness, activity, and curiosity are different in every animal. Depending on what type of crabs you have, you can also observe burrowing, hunting, and other activities.
7. Not expensive
While you could invest hundreds of dollars in a rare fish with specific housing and food needs, most crab species cost little if not nothing.
8. Beautiful and Unorthodox Pets
Crabs are exotic pets that do not pop up immediately in our minds when it comes to keeping pets.
Indeed, some people are full of surprises. Their interests are different from the usual typical kind of people. They do such different things which make the other person go in awe. An example of such type of people is who like to keep unconventional pets.
Cons
Keeping crabs is not always sunshine and rainbows. Despite their simplicity, the following should be considered before owning a crab:
1. Handling
Crabs do not enjoy handling. You cannot pet it like conventional pets. They are not pets you can play with.
Therefore, NEVER take them out just because you want to. You should NEVER lift them up by their legs or claws! They can lose a limb by autotomy.
Crabs are not social to humans and cannot be trained.
Handling your crabs often causes stress, in its turn, it can trigger an aggressive reaction such as nipping or an escape attempt.
So, if you need a pet you can carry around, a crab is not a good choice.
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2. Aggressiveness
I have already touched on this subject earlier when I was talking about socialization. Many crab species are territorial and aggressive to each other and other tankmates.
You do not want an aggressive crab that spends its day chasing and harassing and stressing everyone else around.
Unless you are an experienced aquarist, you should not attempt to house multiple crabs (which are particularly aggressive) in the same tank.
However, if you are still willing to take the risk, you will need to provide a lot of hiding places. I mean a lot – a lot, so the crabs can hide from each other. In addition, multiple crabs should be kept in groups of one male with multiple females. It will reduce aggression.
Generally, the ideal situation is a species tank only.
While some crabs may not kill their tankmates (other crabs, fish, snails, shrimp, etc.) right away, it will lead to problems eventually.
| Species | Temperament |
| Thai Micro crab | Very peaceful |
| Pom Pom crab | Peaceful |
| Fiddler crab | Peaceful |
| Red Devil crab | Peaceful (don’t like other crab species) |
| Vampire crab | Peaceful (don’t like other crab species) |
| Red claw crab | Aggressive / Territorial |
| Halloween Moon crabs | Aggressive / Territorial |
| Panther crab | Aggressive / Territorial |
| Matano crab | Aggressive / Territorial |
| Rainbow crab | Aggressive / Territorial |
| Red Mangrove crab | Semi-aggressive |
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3. Not Compatible with Aquatic Plants
Lots of crabs are not plant safe and not compatible with plants.
It can be a huge mistake to keep them in planted tanks without preliminary research. In the aquarium, some species become lawnmowers; they can eat, cut, and uproot basically any plant. Even more, some crab species are voracious vegetarian-type eaters.
So, if you want to keep plants in the tank, get something that when one or two get destroyed it will not be a big deal. Buy some cheap plants and replace them once in a while. Another option is to focus on floating plants or fake plants.
| Species | Compatibility with plants |
| Thai Micro crab | Yes |
| Pom Pom crab | Yes |
| Fiddler crab | Yes |
| Red Devil crab | Yes |
| Vampire crab | No |
| Red claw crab | No |
| Halloween Moon crabs | No |
| Panther crab | No |
| Matano crab | No |
| Rainbow crab | No |
| Red Mangrove crab | Yes |
4. Breeding
With some exceptions, the process of breeding crabs is very difficult. Some species have never been bred in captivity because they must migrate to the ocean to release eggs that hatch into planktonic marine larvae.
Therefore, keep that in mind when you choose crabs as pets.
| Species | Breeding |
| Thai Micro crab | Difficult |
| Pom Pom crab | Difficult |
| Fiddler crab | Medium |
| Red Devil crab | Difficult |
| Vampire crab | Difficult |
| Red claw crab | Difficult |
| Halloween Moon crabs | Difficult |
| Panther crab | Difficult |
| Matano crab | Difficult |
| Rainbow crab | Difficult |
| Red Mangrove crab | Difficult |
5. Molting and Special Care
Crustaceans do not grow like other animals.
All crabs have a heavy exoskeleton that ensures protection of the internal organs, unfortunately, it also limits the growth of the animal.
In order to grow, they have to shed the old exoskeleton in a process called molting. Molting also provides an opportunity to repair damage and to replace lost appendages.
Keep in mind that, during shedding the old shell and right after it, they are extremely vulnerable. This is the most stressful and important part of their life.
So, you will have to provide a lot of hiding places or they can easily fall prey to their tankmates.
You have to remember some rules, like:
- NEVER disturb your crabs when they are molting.
- When they prepare to molt they usually hide. So, do not panic even if you have not seen them for a few days in a row.
- Keep putting and replacing food in the tank! You never know when they can come up from the molt.
- Keep giving them calcium-rich food.
- Also, do not remove the old exoskeleton from the tank. It contains lots of minerals and your crabs will eat it later.
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6. Humidity
Do not forget that semi-terrestrial crabs also need stable humidity around 70% or higher. They need moist, and humid air to breathe.
This is one of the reasons why people fail to keep them for a long time.
7. Escape Artists
Crabs are natural escape artists. They excel at it.
So, a tight-fitting lid is essential in order to protect themselves and your home.
Selecting the Right Pet Crab
You need to understand what kind of environment (aquarium or paludarium) they need.
If you have never owned crabs before, learn more about the food preferences, habits, bedding, temperature, etc. needs for your new pets. Check the life expectancy of the crab species you would like to keep.
If you are a beginner, it would be best to select a species that is neither fragile nor harmful.
Important: if you have kids in your house, crab pets belong to the “look but DO NOT touch” category.
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In Conclusion
There are many crab species on the pet trade market. They differ in size, colors, and personality traits. They are also low-maintenance pets.
All this sounds very appealing to lots of people, as a result, they get their crabs on impulse, and as soon as the novelty wears off they stop providing enough care for them.
Please, do not do that. Do your research. Weigh the pros and cons beforehand.
On my blog, you can find detailed articles on many species, not just the ones mentioned in this article.
Let me know if you have any questions.
You don’t explain if they need salt water or freshwater, if they need air to breath or not, what they eat ? They need sand or rocks? Do they need a place to come out of water and go back when ever they need
Hi Alfredo trevino,
This article had a different focus. It is not possible to put everything in one article.
On my blog, you will find all answers to these questions.
Every species is different and requires specific requirements.
Check out my article “10 Questions to Ask When Buying Aquarium Crustaceans“, there will be references to many crab species as well.
Best regards,
Michael
What about hermit crabs? Are they friendly?
Hi Breez Henriquez,
As for hermit crabs, they are generally considered social animals and it is recommended to keep them with their own kind as it can reduce their stress and help them behave more naturally. However, even with these crabs, things may not always go smoothly, especially if they differ greatly in size or belong to different species. Therefore, it is recommended to observe them closely at first to assess the possibility of keeping them together.
Best regards,
Michael