Saltwater / substrate issues?

[omarhdz]

Hi there... After thinking about for a while, finally I got three small crabs from petco but I realized one of them has two missing legs and its small claw tips seem broken. These wounds don't seem to have happened recently but this crab is still active and likes to climb. I have them in a 5 gallon tank (the only size I could get by now until I get a bigger tank), it's covered with a mesh lid and plastic wrap to keep humidity inside, (now it marks 85% humidity, 70F) hygrometer and thermometer, coconut fiber and beach sand mixture moistened in instant ocean salt water, two small clams filled with fresh and salt water, a few coral pieces in them, a fake cave I took from my old aquarium, a small heater on the right side of the tank, extra turbo shells (all boiled), a small cuttlebone... Almost everything they might need. I give them fresh mango, boiled carrot, oatmeal (they love it!), dried bloodworms (these are the first thing they eat), grapes, apple, plain chicken, dried krill and baby shrimp, well, an organic diet and no commercial food at all. The only one I use is hikari and t rex fruit salad. I'm thinking about offering them more options. I'm a little worried about the salt water. I mixed it according to the directions (1/2 cup per gallon) but my crabs don't seem to drink it, they use all the fresh water instead. I diluted the salt water mixture by adding a little bit more declorinated fresh water but they still are not interested in it. Maybe it's too salty, maybe the substrate is as well, I'm not sure and I keep worried about my little pets. I don't think they are stressed at all since they are quite active at night and eat and drink, and they respond by quickly returning to their shelter when they see my shadow. I'm not a new crabber, I got my first two hermit crabs four years ago and I've been researching a lot about their proper care. Should I need to change the substrate or making "less salty" saltwater? I don't have a hygrometer. Maybe they are just getting used to their new home.

[CallaLily]

Hello.

This thread explains the importance of saltwater: viewtopic.php?f=25&t=92553. Ideally you want water dishes that are deep enough for your largest crab to submerge, providing easy ways in and out. At a minimum, you should have dishes where they can at least easily swap out shell water. They tend to bathe and soak in the saltwater, especially in preparation to molt. They also use both pools to balance the ratio of salt and fresh water in their shells to their liking. Keep mixing the Instant Ocean per directions. It's also ok that you've initially moistened your substrate using properly mixed saltwater. Just be sure to only remoisten and mist with fresh from now on because the salt will not evaporate and can build up to unsafe levels over time if you keep adding more. That can lead to burns on your crabs and you. The other thing to remember is they are still adjusting to their new surroundings so it may just take them a little time to find everything and make full use of it.

There are a lot of other great articles on crab care here: viewforum.php?f=51. It's really worth taking the time to read through them all.

There are a couple things I'd like to mention based on your description of your crabitat.

I see you're already aware that your tank is a bit small. Try looking out on sites like Craigslist or at yard sales for larger used tanks for low cost. Sometimes you can find really good deals this way and all the tank needs is a good cleaning.

70F is a bit low for them. You'll find they really enjoy temperatures 75-85F (for Purple Pinchers - other species may need slightly different temp range), with crabbers seeing the most activity around 80F.

Welcome to the HCA! I look forward to your posts and hope you'll share pics of your crabbies.

Edit: forgot to say your crab with the broken little pincher and leg tips should be just fine. Those are common injuries that are a result of their long journey from the wild to the pet store. They'll regrow during your crab's next molt or two.

[omarhdz]

Thank you for your good advice! I'll look for another tank soon since new ones are expensive at stores. I don't add any saltwater on the substrate, just fresh water as you said... About temperature, I think the numbers I gave are wrong. The thermometer marks slightly more, about 80F and the small arrow keeps within the yellow band, not the blue or red ones but I will try to adjust the temperature of my room as well to get more consistent temperatures. They are quite active at night when everything is quiet, love to rearrange the small cholla sticks, and use one of the shells to block their cave entrance.

Again, thank you for the info, it will be really useful.

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[soilentgringa]

Hi! Everything Calla said is great. Did you calibrate your hygrometer by chance? If you mix a teaspoon or so of salt with a few drops of water (enough to make it stick together but not runny) and put it in a little bottlecap or something like that and put it in a ziploc bag or tupperware with lid overnight, the humidity should be 75%. If it isn't, take a tiny screwdriver and adjust the dial until it is on 75% after 8 hours in the bag with the moistened salt.

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[omarhdz]

Thank you! I didn't calibrate it, just bought it and sticked it on the wall but it's not a bad idea calibrating it so I'll give it a try. It marks a warmer temperature, around 79 or 80. By the way, my room has a warmer temperature than the rest of the house. Since I changed it my crabs are more active but they remain hidden or rest on the cholla sticks during the day, but they become more active at night, emptying the water shells every morning. They are using the saltwater finally! They also eat a lot and enjoy some fresh grape and boiled carrot and one of them has buried itself, perhaps it's molting and I haven't seen it for four days. I don't think it's dead since there is no any fishy smell... I'm getting a bigger tank soon for them.

I have another question, how often should I give them saltwater? I'm afraid they can carry it into the substrate (which I moistened in saltwater already before putting it into the tank) and make it even saltier. I read the salt will build up as water evaporates and it can kill the crabs.


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[soilentgringa]

They need saltwater 24/7 just like freshwater. If you provide pools deep enough for them to submerge and a way out, the drips of water coming off the crab isn't enough to cause a substantial salt buildup in the sub. Spraying every day with salt water is a different story and shouldn't be done at all. There are like 70 some odd elements that they need in the saltwater. They also need protein and calcium sources daily.

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[CallaLily]

drips of water coming off the crab isn't enough to cause a substantial salt buildup in the sub. Spraying every day with salt water is a different story and shouldn't be done at all.

This is exactly what I meant when I spoke about saltwater above. It's only a concern if you are repeatedly adding more and more sw to the substrate. Little crabby spills shouldn't be enough to cause problems. Sorry for any confusion.

[omarhdz]

No problem and thank you for the info. My crabs eat different things that are safe for them. I provide calcium by putting a piece of cuttlebone, add some powdered on their food. Plain boiled chicken, fish, freeze dried bloodworms, dried shrimp and krill are always their favorite foods. They also love boiled carrot (no skin on it) and I know it's good to enhance their color. I'm thinking about offering them some squid and mussels. Should I boil them first or can the crabs eat it raw?


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[megmaholm]

I'm thinking about offering them some squid and mussels. Should I boil them first or can the crabs eat it raw?

They can have it raw or cooked; your choice. Sounds like you're offering plenty of protein and calcium, which is good, but they'll also appreciate a good variety of fruits and veggies