10 Reasons Why Your Hermit Crabs Do Not Need a Sponge

I remember picking up my hermit crabs from the store like it was yesterday. I was intrigued by the little guys and asked a store employee what she knew about them. The first thing she told me about was about the glorious sponge and how I needed it for my hermit crab tank. One week later they were in the garbage bin.

You may be confused as to why. It is because I had several complaints, 10 to be exact. They range from the sponge being bulky and over-priced to the fact that they barely do their job.

Call me pessimistic, but I’m not alone with this opinion. Many hermit crab owners are throwing away their sponges because their crabs do not need them! There are plenty of other parts to a hermit crab enclosure which accomplishes the job of a sponge far more effectively.

Yes, you heard me right. Hermit crabs do not need sponges for 10 reasons:

Hermit crabs prefer bowls.
They harbor bacteria.
They’re overpriced.
They’re tedious to clean.
They take up too much space.
They dry out rather quickly.
They get torn to bits.
They barely increase humidity levels.
They’re an eyesore.
They’re an annoyance.

So buckle up, I’m going to dive into each reason as to why I would never recommend a hermit crab sponge to my own worst enemy… if he ever gets hermit crabs.

1) Hermit crabs prefer bowls.

Hermit crab sponges are supposed to provide your crabs with a source of moisture keep their gills wet and give them a source of water. What if I told you that hermit crabs prefer using bowls of water instead of a clumsy sponge.

Don’t believe me? Well, hermit crabs survive just fine in the wild where there aren’t any sponges to drink from. Instead, crabs find their water in puddles of collected rainwater on the ground, in plants, and wherever else they can find it.

Bowls of water and saltwater give your hermit crabs a taste of their natural habitat. They give your crabs plenty of water to drink and extra to store in their shells for later. This extra shell water comes in handy because it keeps their gills wet which helps them breathe. Two clean bowls of freshwater and saltwater also give your crab the option to take a dip if needed. Hermit crabs have been known to take a swim to clean themselves.

The only downside to bowls is that they require a bit of work as well. Every 2 to 4 days, or whenever there’s a notable amount of substrate floating in the water, you need to replace it with nonchlorinated water. One bowl needs saltwater, and the other needs fresh water. The saltwater can’t just be regular water with a pinch of table salt. Instead, hermit crabs need aquarium salt to make the water meet the correct salinity.

2) They harbor bacteria.

This was what completely turned me off from sponges for me, and most other hermit crab owners. Being a damp, moist object in a rather unsanitary environment makes your sponges beacons for bacterial growth.

“Sponges just harbor bacteria. Ditch it” – Hermiesguardian – Hermitcrabassociation.com

This can become a threat to your hermit crabs who love to chew and occasionally drink from sponges. My crabs used to clean themselves with their sponge by rubbing their claws and legs against it, just adding to the bacteria frenzy.

Hermit crabs also like to push it around, which causes substrate and whatever’s lying on it (hermit crab poop, mold, rotting food) to stick to it! In just a couple days your sponge will be a rolling biohazard your crabs will wrinkle their antennas away from in disgust.

3) They’re overpriced.

At pet stores, online, everywhere! I believe that hermit crab sponges are priced for far more than they’re worth. They are just another scam in the already corrupt hermit crab industry.

It costs at minimum $4.00 or a single sponge the size of a golf ball. That may not seem like a lot for some people, but to truly get the best use out them you will need around a dozen spare.

I mentioned before how they become a biohazard after a few days, which means they need to be changed out regularly. Unless you want to go through the tedious cleaning process every other day, it’s best to have some spare.

You can get a 12-pack of kitchen sponges at any old hardware store 4 times the size of a hermit crab sponge for $8.00. That’s $1.50 per sponge! Why do hermit crab sponges cost 4 times as much as a regular sponge when they’re a fourth of the size?

If you happen to know anyone shopping for their hermit crabs, make sure they stay away from sponges. They’ll suck away their money, which could have gone to a couple of nice hermit crab swimming pools, moss, tasty treats. Etc. All of which would have done a much better job at keeping their crabs watered and their tank humid.

4) They’re tedious to clean.

I mentioned before how often you need to clean your crab’s sponges, but did I also say how tedious of a chore it is?

Each sponge takes about 2-4 minutes to clean. That may not sound terrible, but if you’re cleaning a dozen sponges you will be there a very long time. Each sponge has to be thoroughly rinsed with hot water to remove any dirt or whatever else stuck itself on the sponge. Be sure to wash your hands afterward; you have no idea what grows on those things. After each sponge is rinsed, it needs to be squeezed of all its moisture then left out to dry. Once they are bone dry, microwave them on a microwave-safe plate for two minutes on low power. This will zap any bacteria growing on the sponges.

After that, dampen two with dechlorinated water and place them back in your crabitat. The rest need to be sealed in a mesh container, similar to the one you would find oranges in at the grocery store. This allows air to flow in and out, which dries out your sponges even further.

Now, don’t get me wrong. I always take the time to keep my hermit crabs happy and healthy. It just bugs me that I already mist their substrate and replace their water bowls every other day, which does a much better job at maintaining the proper humidity. Why should I have to worry about sponges?

5) They take up too much space.

Believe it or not, the sponge you got from the pet store is most likely way too small to affect the humidity of your crabitat. From what I’ve seen, you need a baseball-sized sponge in a 10-gallon to maintain the right humidity. These are impossible to find as it’s much more lucrative to sell you three $4 golfball-sized sponges rather than a single large one.

If you are lucky enough to find a large sponge, or just went with 3 smaller ones, it takes up way too much room. Think about it. You need shelter, decor for hiding spots, extra vacant shells, toys to climb on, and 3 bowls: one for food, one for salt water, and one for freshwater. That already takes up most of the enclosure, leaving little room for 3 sponges. Your hermit crabs need to feel like they can roam around like they could in the wild. Otherwise, you might find some very stressed and homesick crustaceans. You wouldn’t want your pets to feel crabby (get it?), would you?

6) They dry out rather quickly.

The entire point of a hermit crab sponge is to stay damp. Otherwise, they cannot give off humidity and act as a source of water for your hermit crabs. Wouldn’t it fair to just a tad upset that they end up drying out after just one day?

Sure, you can always wet the darn thing and place it back in the tank, but it just adds another thing to worry about when taking care of your hermit crabs. Plus, you can only do this just a few times before you need to wash your sponge. I proved before how irritable of a task that can be.

Sponges tend to stay wet when they’re in a humid environment. Isn’t that ironic? There are a few ways to keep your sponges, and the entire aquarium, damp that end up doing a much better job than the sponges in the first place. This is the main reason why I traded in my sponges for moss, bowls, and a mister.

7) They get torn into bits.

You’d think that since they are so expensive, they would be just a tad durable. Well, it’s quite the opposite. The sponges either break down and fall apart or get ripped into pieces by your hermit crab’s unforgiving claws.

If you’re set on using sponges, get ready to take bi-monthly trips to the pet store and bring home a few more sponges each time to replace the destroyed ones. Some crabs enjoy ripping into sponges more than others, I am lucky enough to have two crabs who would rather take on their sticks of cholla wood.

To avoid getting your sponges torn to bits, place a few more durable toys in your crabitat. Hermit crabs love using their claws, and rather than using it on their sponges or each other, they should claw away at props and decorations.

8) They barely increase humidity levels.

I said it before and I’ll say it again: hermit crab sponges are terrible at their job. If you are having humidity problems in your tank, sponges are not the answer!

If you are having humidity problems, do 3 things:

Find a clean spray bottle and mist the substrate of your tank until it’s damp, but not dripping wet.
Shop for some hermit crab moss to hold the dampness in place
If you don’t have a lid, take some plastic wrap and cover the top of your aquarium. This will prevent any humidity from escaping.

This worked so well that my hygrometer (a device that measures humidity) broke! I had to go with a more durable one that could handle such high humidity levels. I wrote an entire review on it, click here to check it out. It would take several baseball-sized sponges to even come close to the increased humidity my hermit crabs now enjoy. It’s also a lot less work. Now, all I have to do is give my tank 2-4 fine sprays every other day. I’m a bit at the tanks’ mercy of how much humidity it can handle. If I start to see too much condensation, I lay off for a day. Too much condensation can cause flooding.

9) They’re an eyesore.

Have you ever seen a sponge in a hermit crab aquarium? When I still used sponges, most people would peer into my crab’s glass cage and ask, “What is that?” while referring to my 3 sponges scattered throughout my tank.

I use coconut fiber for my bedding, which made my sponges seem like an unnatural lump in the center of my cage. You can’t appreciate the contrast between the green decor and my brown substrate with a large, lumpy, muddy-brown colored sponge lying in the middle of it.

I tried hiding mine in their shelters, under a leaf, or anywhere out of sight. This would only lead to me forgetting where it was then finding a lump of mold growing on my sponge a few days later. Meanwhile, people would ooh and aah at the beautiful ceramics in my tank- one filled with freshwater, the other with saltwater.

10) They’re an annoyance.

This may be a combination of the previous reasons, but it’s still reason enough to be its reason. Keeping up with hermit crab sponges is like running on a neverending treadmill.

They’re a chore and a half to keep clean, wet, and effectively store them. At the same time not providing any real benefit to your tank. They take up too much space, look like a lump of dried up poop, and cost too much money.

Wow. I feel very pessimistic after writing this but it’s the truth. If you’re new to taking care of hermit crabs, don’t make the same mistakes I did. Spend time researching what your crabs need to stay happy and healthy.