New hermit crab owner with a few crabitat questions

[hermie3]

Hello!

We inherited 3 hermit crabs from my son's school. My son (age 5) has been OBSESSED with crabs (all kinds) for the last 2 years. So he is thrilled to have the hermit crabs at home. He says he wants to be a hermit crab scientist when he grows up. For my son's rapidly approaching birthday, I am looking to get a 20 gallon aquarium with a glass lid to put them in. The enclosure they sent home with us isn't where I want them to be permanently.

I have a few questions (please forgive me if they are silly- just want to be sure I'm doing the right thing!).

1. Temperature. I am planning on getting a UTH to put on the side of the tank. I have read that a lot of people like Ultratherm- but I am open to any other recommendations on brands. A few questions, here... What size pad should I get for a 20 gallon (long) tank? At what level should I place the pad (some sources I have read say half above/half below the substrate, other sources say completely above the substrate)? And, it sounds like I put the pad at one end of the tank (to create a warmer and cooler side). I am planning on putting the water pools at one end of the tank. Should that be the heated or unheated end? Lastly, thermostats... are they recommended? If so, where do I place that? Warm end, cooler end, in the middle? Above substrate, buried in the substrate?

2. Substrate- should it be an even/level (amount) the whole way through? Or deep end and a shallower end? If deep/shallow ends, does it matter which end has the water and/or UTH?

2. With a glass lid (hoping to help control humidity that way), how do I ensure enough proper airflow (fresh air) for them?

3. Lights- are they needed? If so, recommendations? The crabs are in our main living area (not in front of a window in direct sunlight) but the room has plenty of natural light, especially in the summer months. Winter in Seattle is pretty gray and the days are short. If lights are recommended, any tips? And, are there any "night" lights that can be used if my 5 year old son wants to watch them in the evening? Ours seem to be more active at night (and I don't want him to use a flashlight to watch them- I think that would startle them).

4. Lastly and probably a stupid question. I am using Instant Ocean for my saltwater. How long does a mixed up batch last for? It is in a sealed container to minimize evaporation.

Okay, I think that is all for now. Thank you for patiently reading through all these questions. These little guys had very little correct in their habitat at school and I want to make it right. Thank you!!!!!!!!

[asiankanye]

I can answer the lid question and the salt water question. Hermit crabs have modified gills for very humid air, so you could chose to have some holes if you wanted to, but I remember it not being required. You should replace your water every other day, and if you have a bubbler once or twice a week. So the water should last long enough between changes. I’m not the most accurate source, so not all of this information is guaranteed to be correct.


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[JoeHermits]

Hope these help!

1. Ultratherms or Fluker’s will work. You’ll want one that’ll cover the entire back, so about thirty inches long (or a little less) for a twenty long. It’ll heat the tank and still create a small gradient.

It can be placed above or below the substrate line, but placing it below the line can cause the substrate to dry out.

Water pool placement doesn’t really matter, but closer to the heat mat can increase evaporation, which can help boost humidity.

A thermostat can be useful, and if you have the funds I would recommend one. I find it’s easiest to keep the probe next to the thermometer so you know they’re both reading the same, but just above the substrate (where the crabs are) is ideal.

2. Substrate should ideally be level. Its purpose is to protect molters, so having more volume is better.

2. Hermit crabs breathe through modified gills. Unlike reptiles, they can get by with reduced air flow. The air will recirculate itself when you open it for maintenance.

3. If your room has natural lighting during the day that will be sufficient. If you’re worried that they won’t get enough light during the winter you can invest in an aquarium hood or LED.

If you can’t see them at night by your window alone, you can try getting a blue reptile night bulb, which has more subdued lighting. Note, however, that they can still see the light. It’s useful for viewing but should be turned off when not in use so as to not disrupt their circadian rhythm. They’re too bright to replicate moonlight and the crabs don’t need it, anyways.

4. Saltwater won’t go bad or anything, if that’s what you’re wondering. I’ve never experienced any algae or diatoms in my stored water.


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[hermie3]

Thank you, JoeHermits!

Those answers were super helpful!

I do have one more temperature related question. The tank they are currently in is at 70 degrees. And, I know they had just been living at room temperature in the classroom, prior to coming to us. Do I need to do anything to acclimate the crabs to the warmer temperature of a properly heated tank, or can I just put them in the new tank with the UTH turned on?

Thank you!!

[JoeHermits]

You can put them straight in. Acclimating them doesn’t have any additional benefits.


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[hermie3]

Thank you!!