13 days molting and mites have shown up

[SF16400]

First let me say these are my teen daughters crabs, she's done the research and cares for them. I don't pay much attention so I am not going to know much details in the questions below. I only pay attention enough to make sure there's nothing dead and to keep on her if I think things aren't being cleaned.


What is the volume of your main tank?
10 gallon

How many hermit crabs do you currently have? How big are they?
4 crabs - largest is about the size of a ping pong ball

How long have you had the hermit crab(s) that you are concerned about?
3/4 months I think - they are my daughters, not entirely sure

What substrate or combination of substrates are you using? How deep is it?
half sand (bought at a pet store) half coconut fiber; about 2-3 inches

What do you feed your hermit crabs?
hermit crab pellets, freeze dried worms, occasionally fresh fruit in non-summer months

Do you use distilled, bottled, tap or other types of water?
tab water with additives from pet store

If you are using a dechlorinator, what brand is it? Does it state to remove all heavy metals, chlorine and chloramines?
Have no idea on brand, just use the amount it says to use

What brand of sea salt are you using to supply your hermit crabs with salt water?
Again - no idea on brand.

What heat source are you using and where is it positioned?
Currently nothing, was using heat pad on back left side of tank. It died in May and haven't replaced it yet since it's 90+ degrees and high humidity in my area

Have you calibrated your thermometer(s) and hygrometer so that you can interpret accurate readings?
No idea how to do this -

What is the air temperature range and humidity inside the tank?
Falls in the 'yellow' on the thermometer and hygrometer - this is supposed to be the right temp.

What is the highest temperature that the substrate near the heat source reaches?
I have an air thermometer -

Do you have any photos of your tank or hermit crab(s) of concern? If yes, please attach them to your post.


We had some sort of mites about 6 weeks back (very tiny, about the size of the tip of a straight pin, tan in color). We did a deep clean, baked or boiled everything that could be. Let the tank sit in the sun for several hours before cleaning. And bathed all the crabs twice a day for three days. This was all information I found on 3-4 different websites.

Everyone moved back into the freshly cleaned tank and seemed like everything was fine. About 4 weeks later one of the crabs started molting. Since then, one at a time, all the others have buried themselves for molting. It'll be 2 weeks tomorrow since the first one began molting. This morning I noticed mites on the rim of the tank again.

I've pulled everything out that I could to clean and did a thin scraping of the substrate to pull the top layer off in hopes of pulling out eggs. I know how quickly these things multiply and how bad they are for the crabs. I also know how dangerous it is to move a molting crab. Please advise, what else should I do?

[emmac350]

Are you sure they're mites and not fruit flies? Flies can be attracted to food in a crab tank. Did you see the mites on the crabs themselves? Mites would be back in the shells on the soft abdomens, whereas flies just act like you'd expect fruit flies.

[ladybug15057]

I agree with Emma, and to make sure all mites are tended too one should do a total deep clean, and bath the hermies once a day with ocean/sea water. (not the mixtures they sell for hermit crabs. It should be a regular ocean/sea salt sold for salt water fish tanks) Everything should be boiled that can be boiled, baked that can be baked, or washed with distilled vinegar that cannot be boiled or baked until all the vinegar smell is gone. (including the tank)
Did you dip the fiber bedding in boiling water, and letting it cool prior to using? Some have noted transporting pests in their tanks that are hidden in the fiber, as well as sand should be baked for pests prior to using.