Gulf Coast Hermit Crab Adventures

[mnemosyne9]

So I live in Louisiana, and I made a trip to Biloxi, MS this past weekend to spend a few hours on the beach. Anyone who's been to a gulf coast beach knows, they're covered in trash, smell like death, and ever since the BP oil spill, they're covered in black sand and water so thick and sludge-y you can't see the bottom of ankle-deep tide pools. But the gulf coast is the only real beach for days, so when we dear broke folks of the south get the beach bug, we put up with it.

Anyways, more to the point- between my crew and the random little kid whose moms didn't want him taking anything home, we ended up finding 1 snail, one regular crab (main body about 2-3" wide, hiding in a piece of trash), and ~40 shells, about 5-10 of which are empty and the rest are hermit crabs. We put the regular crab back, as we weren't all that confident we could take care of him, and ended up bringing the rest home.

I don't need lectures on the detriments of abducting wild animals from their natural habitat; normally I wouldn't do such a thing, especially in such large quantities, simply out of concern for upsetting the local ecosystem. In this instance, I took the 30-some-odd crabs home out of a combination of pity that they live in such a disgusting,toxic place, not wanting to disappoint the cute, crystal-blue-eyed kid who worked so hard to help us find them, and push from my family. The point is, I have them now, and I'd like to keep them alive if I can.

I feel like I have a decent chance, being in the same climate zone. Of course I don't expect all of them to survive the system shock that will come with acclimation to clean water, but hopefully at least some of them do. Most of the gulf water I had put in with them ended up spilling out, but I have enough to get by for a few days, and I might be going back next weekend to take photos (at which point I could get more natural gulf water to aid the acclimation process).

Since, if my memory serves, hermit crabs don't require super deep water, I was thinking I might get a large storage tub or two, and house them in that for the extra space. With there being so many, I'm concerned that they'll fight if they don't have enough space. What I'm having the most trouble with is coming up with a good substrate and food source for them; what I read online suggests that they would be omnivores, which holds true with the fact that I found the snail being attacked by one of the crabs. Would pellets cover the dietary staple? Or, with them being wild caught, will I need to mimic their natural food sources as closely as possible?

I also need to acquire a few dozen empty shells for them, in sizes from 'nickel' all the way up to palm sized.

Anyway, to wrap up this post, if anyone has any advice on taking care of these guys, let me know! I'll post photos of them later.

Also, I believe the snail is a Moon snail, but I haven't seen his body all the way out yet, so I can't be sure. I found a couple of clam-based frozen fish foods I could try to get for him, if that is indeed his species.

[wodesorel]

Since they are marine you'll get better advice on a reef forum. You'll need a proper saltwater filter, testing kits, live rock, live sand, possibly UV filtration, a skimmer, a heater, and of course enough marine salt mix to do regular water changes.

Since they have gills water quality is of top priority. Your probably looking at $300 or so to get them set up properly and with enough gallons of water a per crab so they have a chance at living a normal life. Being hermit crabs they will survive for a while now matter how you keep them, but eventually the toxin buildup in the water from their own waste will cause phsycial damage and will prevent them from molting properly which will kill them. That is combated by having enough water to dilute and proper filtration (biological filter, not physical) to keep it within safe limits.

[mnemosyne9]

I didn't think about asking on a reef forum, thanks for that idea.

I have full plans on setting them up with a filter, master test kit, etc- I'm decently familiar with freshwater fishkeeping, this just happened suddenly, is all. I'll be getting some aquarium salt today so I can give them at least a bit more water. I want to try to switch them slowly due to the massive difference in water quality from the gulf- switching them to straight clean water too fast would probably kill them just as much as dirty water would.

I have a 10g and supplies so that all I need to set it up is a filter and lid; I was going to put the snail in that, and get something bigger for the crabs. I will still need to get a saltwater test kit, as like I said, I'm more used to keeping freshwater, but that and substrate, deco, etc are the main things I still need to acquire. UV filtration is definitely something I'll have to look into. I may put some of the crabs back if I do go back next weekend, depends on how hard I have to fight my family to get them to agree on it.

How many crabs would one generally put to a ~40g tank?

[wodesorel]

No one here has massive marine colonies. You'd have to check with a reef group and see what they would recommend. I know that they are considered semi aggressive and they will go after each other if overcrowded. They're probably thinstriped hermits so can get up to 4 or 5 inches when grown. I can't imagine they would be much better than land crabs in terms of sharing space, so figure a gallon a crab if they are all super tiny and for full grown maybe 5 total in a tank that size, possibly less.

Keep in mind too that there are legalities in collecting and returning animals to the wild. You should have had a permit to take them first and there are daily collection limits, I believe it's only a few at a time with a fishing liscence. Returns are usually prohibited as well as diseases or parasites can be brought back and cause havoc in wild populations. That one is a major issue so please think hard before bringing any back. I personally don't recommend it. Find an aquarium or other enthusiasts who would keep them in captivity instead.

[Hermias_mom]

A few thoughts for you -

I've been haunting my local reefkeeping shop (saltwater aquarium shop), and doing a lot of research on the reefkeeping forums, so I can tell you what I've seen and read in terms of marine hermit crab care. Someone who's had a properly set up saltwater aquarium for some time (5+ years) can probably tell you more. A lot of folks get into reefkeeping, but they don't buy a big enough tank to start, or give it enough attention, or they make some other mistakes, and then get frustrated a year or two in when they loose all their fish/corals, which leads them to give up reefkeeping.

I was considering reef-keeping, but it seems too time and money intensive for me at this time. But if you want your hermit crabs to thrive, here's what I can tell you. I recommend you get some Instant Ocean instead of the Aquarium salt - there are some significant differences between saltwater aquariums and freshwater aquariums, and the Aquarium salt is only appropriate for the freshwater aquariums, mainly used to help fight diseases in fish, I believe. Mix the Instant Ocean according to package instructions and use that as the water for your aquarium. Marine hermit crabs require the full saltwater aquarium setup if you want them to thrive, including Instant Ocean, a biological filter as well as physical filter, and there's a whole ecosystem of beneficial bacteria that needs to get established properly so that the tank can cycle and waste buildup doesn't end up eventually poisoning fish/crabs/coral. Live sand and live rock are the basics of it, but the larger the aquarium the better. Smaller saltwater aquariums (40-20 gallons or less) are actually much more difficult to keep functioning properly than large ones. And most folks keep a large extra tank down below the display tank which is plumbed into the display tank to increase the volume of water that is part of the ecosystem, which is important for having healthy tank occupants. You may have better success starting out with a 75/100 gallon tank. I'd recommend some serious research on the reefkeeping forums before you start. Having a saltwater aquarium can easily be a $2000-$3000 USD per year hobby, even if you only keep hermit crabs in it. From what I can determine, the main costs are in equipment and upkeep (lighting, heating, and water treatment/turnover), not in the purchase of fish/crabs/coral, though those can also be pricey.

Most saltwater aquarium folks use the hermit crabs as tank cleaners, and prefer the tiny ones. Once they get too big, they start eating the fish and corals in the tank, and I'm not sure they really live that long in captivity, even when captive bred. I've seen 100-200 gallon tanks (properly set up, gorgeous displays from folks that do it for a living) that had maybe 15-30 tiny hermit crabs in them as tank cleaners, along with 15-20 marine snails (mexican turbos, whatever the actual name of the snails that have that shell are), a few fiddler crabs, and a large variety or coral and fish. So that's the amount of loading I'd expect for a healthy 100-200 gallon reef tank. Maybe it's not so helpful without pictures, but I thought some numbers might help.

Hope this helps. Happy researching!