Alright, I'm gonna apologize in advance because it looks like you fell prey to misinformation from pet stores & such.
There's a LOT that needs to change in your tank to make it a good home for your crabbies. Hopefully we can try & keep it as cheap as possible for you, but it is going to involve spending more money.
First things first:
- You need to make sure they're warm. They need to be 75-85F, most people shoot for around 80F as that's where PP (Purple Pinchers, most likely the species your crabs are) are most comfortable. The best way to do this is with an undertank heater, UTH. These ones are most recommended & this is the best site to buy them from -
http://www.reptilebasics.com/ultratherm-heat-pads You can get them from pet stores as well though.
- You need a different thermometer. I can see a strip on the back that looks like one of those stick-n things...those aren't really accurate. It's best to get some gauges or a digital thermometer. You can get a digital thermometer/hygrometer at Walmart for $10 or so, much cheaper than pet store ones. You do need a hygrometer (measures humidity) too, so get one that does both, or get a gauge for each thing.
- On the subject of humidity, it needs to be at least 70%. Most people shoot for 80% with that too. If the humidity is too low, the crabs can't breathe properly through their gills & it damages them. So this is VERY important to fix ASAP. The best way to fix humidity is to cover the lid (you do need a lid for the tank) in plastic wrap or tin foil. You can open little holes in it for ventilation, but first thing is to get the humidity up.
- Unfortunately the sand you have in there isn't safe. The best thing to use is play sand from a hardware store. Make sure it's not wet already when you buy it. It's cheap! 50lbs for $5 or so. A lot of people mix the sand with coconut fiber, which helps with maintaining humidity. You want the substrate (the sand & coconut fiber if you get some to mix in) to be at least 6" deep. The rule of thumb is 3 times the height of your biggest crab. That ensures they have plenty of room to dig & molt properly without disturbing each other. When you put the sand in, you need to add water so that the sand is sandcastle consistency - that means you want it to hold its shape when you squeeze it, poke your finger into it, etc. That means the crabs will be able to safely dig a tunnel in it without the tunnel collapsing. This will help raise the humidity in your tank too.
- You need two water dishes that are deep enough for your crabs to submerge themselves. The easiest thing to use are sour cream/butter containers if you have some empty ones. Make sure they're clean & well-rinsed first. One pool needs to be fresh water, one needs to be salt water. Make sure the crabs can get in & out - a lot of people get some plastic sewing canvas (you can get a sheet for less than $1 in craft stores, possibly in the craft section at Walmart, etc.) & use that for ramps to get in & out. You need to dechlorinate the water as well, and you want to use the right thing for salt water, as products sold specifically for hermit crabs don't usually have everything needed. There's more information about all of that here -
viewtopic.php?f=25&t=92553
- Sponges aren't really necessary or great to use, they tend to get a lot of bacteria & are a pain to clean. Most people just throw them away.
- It looks like you're using a commercial food. A lot of them aren't safe or healthy for hermit crabs. You can check this list to see if yours is okay to use occasionally or if you should just throw it away -
viewtopic.php?f=25&t=92555 Crabs are omnivores, and they can eat most things that we do! A lot of people just feed their crabs from their own food, with no seasonings/sauces/etc. You can get dried insects from the pet store, and dried fruit & veggies (check for added salt & seasonings) from grocery stores & health stores. Here are the safe & unsafe food lists -
viewtopic.php?f=25&t=92557 and
viewtopic.php?f=25&t=92556
- When you can, you'll want to get some extra shells to put in the tank. It's best to have at least three extra shells of the right size for each crab. That gives them some options & you won't have them attacking each other to steal the other's shell. You can get good shells at craft stores sometimes. Joann Fabrics has a "Green Shell Bag" that have a lot of green turbos, which is a type of shell that PPs really like. The bag is only $5 or less & should give you a few shells to get started with!
- For tank size, an upgrade wouldn't hurt if you can manage it. But for now, the substrate, water, temp/humidity, and food are most important, I think. Getting those things sorted out ASAP will immediately improve your crabbies' home! Sometimes you can find cheap tanks sold on Craigslist & such, so you can keep an eye out & see if you can get a good deal on a 20-30 gallon.
In case I missed anything, here is the general care sheet for Purple Pinchers -
viewtopic.php?f=51&t=92452
I know that's a TON of information! A lot of people find the forum & realize that they have a lot of things wrong with their set up. Pet stores & other places that sell crabs give out pretty terrible care advice most of the time. The important thing is that you found this website and you're interested in giving them a great home.
If you have any questions about anything, feel free to ask! Everyone here is very friendly & helpful, and many people started out in the same place as you, and understand the frustration from having to change everything & throw stuff away because you were sold the wrong thing.
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