HCA: Hermit Crab Association

When we got our two hermit crabs four months ago, we knew nothing and I rushed to learn what I could while not wasting any time getting them into a humane environment. I did the best I could at the time. But having learned more since then, I'd like to make some improvements. Toward that end, I have just purchased a 29 gallon aquarium to replace the 20 gallon long reptile tank we have now. This will provide added strength and allow both deeper substrate and more height to add some climable features.

Here's where I'd like some help:

I want to upgrade to an Ultratherm UTC but don't know what size. The tank is 30" wide and 18.75" tall. I plan to have about 8" of substrate. Should I go with the Reptile Basics 11x23, Bean Farm's 11x29 or something else?

Also, what do you guys use for hoods? Should I get a solid cover, use my reptile tank's grated cover or get a lighted hood of some sort?

You want the 29" Ultratherm so it covers the whole back of your tank. I personally use a glass versa top from drsfosterandsmith.com. I think glass works the best to maintain humidity, but you can always use mesh tops with Saran wrap. I don't have experience with lighted hoods, so I'll let others touch there- but if it's meant for fish, (water resistant) and can hold humidity it should be fine.

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Thanks! I'll pick up the 11x29 Ultratherm. I saw those versa tops when I picked up the aquarium. Do you need to cut/drill holes in the plastic part for ventilation?

The air exchange when you open the lid for feeding should be enough. You would only have to make a hole if you wanted bubbler tubing or a temperature probe to enter the tank.

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I've ordered the 11x29 Ultratherm from The Bean Farm. The plan is to attach it with the silver metal tape used for A/C ducts, unless that sounds like a bad idea for some reason. I also found a large rock/tree branch resin aquarium ornament that has a decently rough texture clearanced at a local pet store. That should provide something for the crabs to climb.

Sounds good.

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I have a 29 gallon tank and the same ultratherm you are getting. I cut a piece of foam board to fit the glass on the back of the tank, for insulation. I covered the tank facing side of the foam with the metal tape for reflectivity and attached my ultratherm to the foam board rather than the tank. I then used regular clear packaging tape to attach the foam to the back of the tank.

I am new to this as well, but I figured it would be easier to remove if I ever have to replace/maintenance the heater. That metal tape doesn't like to come off.

I hope your crabs live a long and happy life!

Brian_T wrote:I have a 29 gallon tank and the same ultratherm you are getting. I cut a piece of foam board to fit the glass on the back of the tank, for insulation. I covered the tank facing side of the foam with the metal tape for reflectivity and attached my ultratherm to the foam board rather than the tank. I then used regular clear packaging tape to attach the foam to the back of the tank.

I am new to this as well, but I figured it would be easier to remove if I ever have to replace/maintenance the heater. That metal tape doesn't like to come off.

I like your thinking! I was planning on using the metal foil tape out of fear the heat would be unsafe with other types of tape. But I Also want the ability to reuse/move the pad. I think I'll try to do something similar.

robinwhiskers wrote:I hope your crabs live a long and happy life!

Thanks! Certainly going to do my part to help.

Okay, I finally got all the supplies in and have built the new tank. Just before the move, I got an order of new shells in and the smaller crab grabbed one. He has been underground since, so I assume he's decided to molt. I did go ahead and move the larger crab to the new tank. So right now, I have both the original 20 gallon long reptile tank and the new 29 gallon aquarium tank going.

The new tank consists of the following:
* 29 Gallon Aqueon Aquarium
* 30" Aqueon Glass Tank Top
* 11"x29" Ultratherm Heat Pad

The substrate is composed of two 50 lbs. bags of Play Sand mixed with one 8.8 liter bag of Zoomed EcoEarth. This seemed to look like like it'd be in the neighborhood of a 5:1 mix. The substrate has an average depth of around 8".

I purchased a 4x8 sheet of 1/2" foil-backed EPS polystyrene foam board that I cut down to the size of the back glass of the tank. I attached the Ultratherm to the foil backing with three small pieces of HVAC metal tape. Then I attached the assembly to the back of the tank with foil tape on all four edges of the foam pad. The heat pad does not make contact with the tank everywhere.

I noticed the glass tank top has quite a bit of gap. So I bought a cheap 28" wiper blade and trimmed the part that wipes the glass. This gave me a square rubber pad with a slot that I could press the plastic back piece of the glass top into to give me gasket that closed the air gap considerably.

Since you guys recommended bubbling the water dishes with air stones, I also bought a Tetra Whipser 10 gallon air pump after doing some research to get an air pump that's quiet. I dropped an air stone in each water dish connected to a hose with a Y adatper and a check valve to prevent water from feeding back into the pump under the tank.

I've begun to feel the little Zoomed analog thermometer/hygrometer we have is not always giving good readings. After reading up on things, it seems all hygrometers are somewhat suspect and getting something that does a decent job can be a roll of the dice. Desiring to buy something local so we could get good measurements of the new tank as soon as possible. I went to Home Depot and bought an Accurite digital temperature/humidity monitor.

Current Conditions:

Temperature: Currently at the surface level of the substrate near the front of the tank, I'm reading 82 degrees. Is this too hot?

Humidity: The front walls of the tank have been about 1/3 covered with condensation. After getting readings in the high 80s, I've removed the wiper blade in order to have air gaps along the front and back of the glass top. I've also turned off the air pump. Right now I'm showing 82%. Does this seem reasonable?

Activity: The large crab is much more active in the new tank. He seems to roam the tank more at night and seems to start his activities earlier in the evening and end them later in the morning. He's also spent two nights near the top of the tank after climbing an artificial tree branch we added to the new tank.

Here's a shot of the tank as it currently looks:



The white shell to the left is the big crab. He's spent the day sleeping in the bowl of moss in that spot.

Looks like a great start! Your tanks specs are good, we usually recommend 80-80 as a base guideline, so that's perfect! My tank runs anywhere from 82-86 degrees on average. I might suggest a few more hides when you can get to it, simply because they are prey animals, and I feel like it makes them feel safer with a bit more coverage- but it really looks nice!

Thanks! Good to hear your temps are similar. It looks like I'm around 84 degrees near the heater and about 82 near the front of the tank. I'm experimenting with bubbling the water and adjusting the air gap in the the glass top to try to get the humidity constant without condensation being an issue.

There is an artificial cave the crab has often used in the tank. The front opening is too small for him, but he can get in behind the tree branch. Here's a better shot of the tank:



I don't know why, but he's been sleeping in the moss in the front for the last three days. But I do want to add more to the tank and will try to think of a design that would provide more hiding places. We added the air fern last night. I also really like the multilevel layouts I've seen others use in their tanks.

We keep two food dishes in the tank that are changed nightly. One is dry food (tonight it's organic oats and an infrequent treat of Captain Crunch cereal). The other is moist food (apples slices and fresh beef).

I'm sure you've notice the crab in the back left corner of the tank. Here are a couple of closeup shots I was also able to get of him through the glass:

Flandry wrote:Okay, I finally got all the supplies in and have built the new tank. Just before the move, I got an order of new shells in and the smaller crab grabbed one. He has been underground since, so I assume he's decided to molt. I did go ahead and move the larger crab to the new tank. So right now, I have both the original 20 gallon long reptile tank and the new 29 gallon aquarium tank going.

The new tank consists of the following:
* 29 Gallon Aqueon Aquarium
* 30" Aqueon Glass Tank Top
* 11"x29" Ultratherm Heat Pad

The substrate is composed of two 50 lbs. bags of Play Sand mixed with one 8.8 liter bag of Zoomed EcoEarth. This seemed to look like like it'd be in the neighborhood of a 5:1 mix. The substrate has an average depth of around 8".

I purchased a 4x8 sheet of 1/2" foil-backed EPS polystyrene foam board that I cut down to the size of the back glass of the tank. I attached the Ultratherm to the foil backing with three small pieces of HVAC metal tape. Then I attached the assembly to the back of the tank with foil tape on all four edges of the foam pad. The heat pad does not make contact with the tank everywhere.

I noticed the glass tank top has quite a bit of gap. So I bought a cheap 28" wiper blade and trimmed the part that wipes the glass. This gave me a square rubber pad with a slot that I could press the plastic back piece of the glass top into to give me gasket that closed the air gap considerably.

Since you guys recommended bubbling the water dishes with air stones, I also bought a Tetra Whipser 10 gallon air pump after doing some research to get an air pump that's quiet. I dropped an air stone in each water dish connected to a hose with a Y adatper and a check valve to prevent water from feeding back into the pump under the tank.

I've begun to feel the little Zoomed analog thermometer/hygrometer we have is not always giving good readings. After reading up on things, it seems all hygrometers are somewhat suspect and getting something that does a decent job can be a roll of the dice. Desiring to buy something local so we could get good measurements of the new tank as soon as possible. I went to Home Depot and bought an Accurite digital temperature/humidity monitor.

Current Conditions:

Temperature: Currently at the surface level of the substrate near the front of the tank, I'm reading 82 degrees. Is this too hot?

Humidity: The front walls of the tank have been about 1/3 covered with condensation. After getting readings in the high 80s, I've removed the wiper blade in order to have air gaps along the front and back of the glass top. I've also turned off the air pump. Right now I'm showing 82%. Does this seem reasonable?

Activity: The large crab is much more active in the new tank. He seems to roam the tank more at night and seems to start his activities earlier in the evening and end them later in the morning. He's also spent two nights near the top of the tank after climbing an artificial tree branch we added to the new tank.

Here's a shot of the tank as it currently looks:



The white shell to the left is the big crab. He's spent the day sleeping in the bowl of moss in that spot.

Your wiper blade idea is brilliant. I wish I thought of that. I had the same problem with a gap and was having a heck of a time trying to keep the humidity up. I finally spent hours scouring the internet looking for a piece of rubber edging that would fit right.


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Brian_T wrote:Your wiper blade idea is brilliant. I wish I thought of that. I had the same problem with a gap and was having a heck of a time trying to keep the humidity up. I finally spent hours scouring the internet looking for a piece of rubber edging that would fit right

Thanks! 28" is the longest wiper blade I could find. Trimming off the actual blade, then cutting off about a 1/4" on one end left me with a rectangular block of rubber with a slot that the back plastic part of the tank top slides perfectly into. I also discovered that you can take the narrow blade part you trimmed and squeeze it into the slot where the glass kid fits into the plastic part. It'll expand to fill the full 30" width. By doing both, the lid ends up fittingl the tank perfectly and creates a near complete seal.