toure the tank


I had a request to post a tour of my hermit crab tank, so here it is! :) Feel free to ask any questions if I miss something or if you’d like more detail on a specific thing or topic of hermit crab care.

Tank Specifics

My tank is a 150g aquarium and I currently have 9 hermit crabs in it. I’m willing to have up to 15 at the moment, as my largest hermit crabs are still either larges or extra larges (not jumbos, the biggest size). Jumbos need much more space per crab because they’re so large.

Heating: There are two 11″x23″ Ultratherm heating mats on the back of the tank, one on each end. They’re insulated with tin foil, with styrofoam over that. ***This is safe for Ultratherms, you have to check heating pad instructions before insulating.***

Lighting: They have a regular LED undercabinet light fixture on the left side of the tank, and a ReptiSun 5.0 UVB light on the right side of the tank. These are attached with heavy duty velcro, though that hasn’t been working great for the UVB fixture lately. UVB isn’t considered 100% necessary for hermit crabs, but it is beneficial for their health & color, so it’s a good idea to include if at all possible.

Substrate: They have a mixture of Eco Earth coconut fiber and playsand, in roughly a 5:1 ratio (sand to EE). It took 600lbs of play sand! Their substrate is about 12-13″ deep. I initially mixed the substrate up with treated Instant Ocean salt water - it’s not necessary, but salt water is thought to possibly help prevent mold growth in the substrate, so I went with it. Doing this won’t introduce enough salt into the substrate to harm the crabs, but you want to make sure any future water added is only fresh water to avoid salt build up.

(Side note, in the future, after I move & re-set the tank up, I plan to mix more things into the substrate, such as crushed oyster shell and leaf litter. This contributes to a more natural mix, gives more nutrients for the crabs while they’re digging, and contributes to an established helpful bacteria system in the substrate.)

Tank Decor/etc.

Left tank (picture 1): Three of their shell shops are in this picture - the large shells is the left corner, the medium shells is next to that, and the little shop at the front of the tank is the small shells. I have no clue how many I actually have in there right now - I would guess at least 50? I’ll have to count next time I clean them!

There’s also a couple fake plants, a fake climbing branch, and several rope/wood bridges (bird toys). They really love those bridges! They also love the coconut hut in the lower right corner (also a bird toy), I usually find 4-5 crabs all crammed in there. And their fresh water pool is on this side. An interlude to discuss the pools:

My water pool containers are heavy duty commercial kitchen food storage containers - we used similar ones at my last job & I remembered them while trying to decide what to use. Food-safe, unlikely to start leaking water & pose a flooding hazard, and very easy to lift & clean! A bit pricey compared to some other options, but they were worth it to me for the ease & peace of mind against flooding. I have two for each pool so that the bottom one stays put in the substrate (to avoid disturbing tunnels) while I change the main pool. Each pool is about 1.5 gallons & they each have an aquarium ornament and a fake plant for the crabs to be able to climb in & out. And they each also have an airstone hooked to air pumps to help keep the water fresher & help with tank humidity. I change the pools once a week. I use Prime to treat the water and Instant Ocean for the salt water.

Middle tank (pictures 3 & 4): They have an aquarium climbing shelf thing against the back of the tank, which I was trying to show with that inside-the-tank picture. I might change that out for a climbing wall of some sort eventually, they only use it a little bit. In front of that is a mopani log, which is the second favorite hang-out. There’s a little hollow in the back of it and there’s usually 1 or 2 crabs sleeping in there. Another fake plant in front of that.

You can also see their most of their food dishes in this picture - the larger food dish is their main food, which gets changed weekly & gets ~3 each of protein, veggie, fruit, and extras. I always make sure there’s at least 2 animal-based proteins, which are VERY important to prevent crabs attacking their tankmates. They have two smaller supplement dishes - one has earthworm castings & mealworm castings. The other has calcium powder and green sand (a mineral supplement - they LOVE it). Those get changed as needed.

Right tank (picture 2): Their fourth shell shop is on this side. It mostly has the lighter colored & less pretty shells that I don’t mind if they get bleached by the UVB light. There’s another fake climbing branch below/behind that shell shop (same one you can see in picture 4). Another fake plant in the back, and next to that is their foraging dish. Every other week or so, I change out the mix in there - I have 4 each of leaf mixes & flower mixes and put a handful of a mix from each category in there, mixed together. Then I add crushed oyster shell and sometimes other things (twigs, bark, snake skin, etc.). Gives them a nice supply of wild foods at all times, and they like to hide under it as well. :) It’s been a staple in my tank since I got my first crabs two years ago.

In the corner is a cork round, though I’m switching that out for a plastic rodent wheel soon. They sometimes climb on it, but not too often, and I think they’d like a wheel! At the front of the tank, they have a fake rock planter that serves as a moss pit (sphagnum moss inside). And in the corner is their salt water pool!

Picture 5 shows the back of the tank with the insulated heating mats and all of the cords for the tank. 2 heating mats, 2 air pumps, and a 12/12 timer that has both lights plugged into it. 

Picture 6 is primarily to show the substrate depth!

I think that’s everything! I hope you enjoyed my hermit crab tank tour & please check your pockets for stowaway crabs as you exit to the right… XD