New Crab Behavior

[JustinL]

Hello,

Recently my family and I visited Rehoboth Beach, DE and my five year old son decided to bring three smallish hermit crabs home from the Seashell Shop. The smallest is about the size of a standard glass marble and the other two are approximately the size of a ping pong ball. Upon our return, we used a ten gallon aquarium as a suitable home for his new pets, removing them from the plastic critter carrier we purchased them in. The substrate at the bottom is moist Eco Earth. We have two water dishes, one fresh and the other a salt solution, both treated tap water. In the tank is a large whelk shell partially buried and a piece of aquarium lava rock for climbing. There are seven different sized shells for the crabs. And, we have been feeding the crabs small pieces of fresh fruit and a corn meal crab feed each night. The temp in the crabitat is 72 degrees F and the humidity is around 90%. Each of the crabs are exhibiting questionable behavior. First, the smallest of the three, has simply buried him/herself since we set up the new habitat with Eco Earth. He/she does not appear to come out, even at night. The middle sized crab switched shells the second day we received him/her, hides during the day, and only comes out to forage during the night. This crab is extremely shy and retreats into the shell indefinitely when approached. Finally, the largest of the three crabs, very active and comes out of his/her shell when picked up, continues to switch between the original shell he came in and another in the tank that is provided. He does the switch-a-roo every other day. Otherwise, this crab is so active, crawling around night and day, climbing on the empty shells, routinely eating, and even investigating the shell of the shy crab. Nonetheless, his/her colors are not nearly as bold or vivid as the smaller two.

Since I am new to hermit crabs and hope to provide suitable conditions for them, can anybody offer insight into the behavior of our new pets.

Thank you

[Trenac]

Welcome!... The behavior that your crabs are showing is normal. The crab that has buried itself may be beginning to molt. Hermits are nocturnal so they like coming out at night more than the day. When they change their shells they are trying to find the perfect fit. Some do this quiet often.

I have 3 crabs now all with different personality. One has buried itself & has yet to change shells. One has changed shell twice in the last week. One has changed it shell once & is very shy.

[HermitHoarder]

Those behaviours sound normal to me The burried one may be molting, but she could also be desressing. If you see her again in a few days, then she was just destressing. But molting can take 5 weeks or more for a small crabby. As for the one who comes out only during the night. Perfectly normal, as they are nocturnal and most crabs do this. I find when I get a new crab they are active day and night as they are exploring their new home, but soon fall into the nocturnal routine once they adjust more. Sometimes it can take 1-2 months for your crabs to feel comfortable in their new home, and you won't see them do much of anything until then.

As for the largest with not so nice colouring. Feed lots of foods high in beta caratine, such as red and orange bell peppers, watermelon ( crabs LOVEEE watermelon), and strawberries. (They like the tops of the stawberries so when you cut them up for your family, your crabs can munch on the tops

You also want to provide a source of protein every night. A good idea is to chop off a tiny piece of whatever you're having for supper (fish, chicken, steak, etc.) and just cook it seperately in the microwave with NO seasoning. Just plain. Your crabs with love that.

Crabs also need a source of calcium at all times. Cuttlebone found in the bird section of your local pet store is an excellent choice. I crush it up and sprinkle it on the food.

Anyways, once your crabby eats some good nutritional foods, he will molt and come up with beautiful colours Make sure your substrate is at least 6 inches deep (It should be 3 times the height of your largest crabby, as a general rule. The depper the better, and it should be moistened to sand castle consistency )

Good luck and WELCOME TO HCA!!!

[CrabbyMom33]

Another thing you can do to get more activity is to get your temperature up closer to 80 for at least a few hours a day. The crabs tend to be more active when it is warmer. Do you have a heat source? If not you will need one in Pennsylvania come fall and winter. A bit warmer temperature will bring your humidity down a bit as well since it is relative humidity and as the temperature goes up the air is able to hold less water. That is actually good because at a constant 90% you are bound to start seeing mold.

[JustinL]

I appreciate the advice each of you has provided. Hopefully we are on our way to successfully keep hermit crabs as pets. I figured I would need to purchase a heat source come autumn. Any suggestions on type and brand?

Also, the local Pet Co. sells hermit crabs, but they have provided only painted "fancy" shells for the crabs. We are thinking of adding a fourth crab to our set up eventually, but not crazy about painted shells, both aesthetically and feeling it cannot be good for the animal. Any opinions or advice on painted seashells for hermit crabs?

Thanks again!

[CrabbyMom33]

I like the Ultratherm heaters, but they are only available online. THeir advantages are: they don't stick on so you can move them from one tank to another, they seem to provide more heat that similar size stick on UTHs, they can be safely insultated behind the heater with polystrene (blue board) to direct all the heat into the tank, and they can be used with a dimmer. That said, on a 10 gallon tank a larger stick on UTH would probably work fine, but just get one that is rated for a much larger tank than a 10 gallon. Maybe someone who has used the stick on kind can advise you on that.

As far as painted shells, the paint is harmful to the crabs. Hermit crabs will pick at and eat nearly everything in their environment. When the paint flakes off it goes into the substrate and crabs will eat substrate. Most crabs will change out of a painted shell if a correctly sized natural shell is available.

You can often find bags of usable shells in craft stores such as Joann's, Michael's, or Hobby Lobby, plus the usually have them at Walmart. The shells are normally in the area with the plastic and silk flowers. Any shells should be boiled in dechlorinated water, then allowed to cool fully, before giving them to the crabs for the first time.

Do you know what type of crabs you have? If you can post some pictures we can let you know. Purple Pincher crabs or PPs mostly like turbo shells with round openings. Compressus (also called Ecuadorian or Es) tend to like shells with D shaped openings like babylonia shells.

As far as adding another crab, since it sounds like you have 2 medium crabs and a small crab, I would not add any more in a 10 gallon tank. If you decide that you want to continue to keep these guys you will eventually need to move to a larger tank even for the 3 you have now.

[JustinL]

Thanks for all of the info and advice and I will begin considering a heater that will work effectively in our crab house. I also have the humidity hovering around 80F. Is this more acceptable than 90F? And, the coconut fiber substrate is still moist to the touch, and I set it up about a week ago. Should the top layer be damp too, or just the bottom layers of substrate?

Further, I believe the species of crabs we have are the ones common on Caribbean and Central American beaches. When I was in college, too many years ago now in the late nineties, I had an opportunity to conduct an independent study on the remote south/west coast of Costa Rica near Corcovado National Park. At points where beach met rainforest, on the Pacific Ocean, living in this riparian zone, where hundreds and thousands of hermit crabs. I believe they were the same species I have now, but cannot be certain. Simply turning over a piece of driftwood or banana palm leaf would reveal so many crabs. Also, banana, fig, mango and other types of fruit trees grew on the forest edges, dropping loads of over ripened fruit. I remember crabs swarming pieces of decomposing fruit along with many kinds of carrion and other organic beach litter. I remember picking up larger hermit crabs the size of a racquet ball! Nevertheless, most of the wild hermit crabs were quite tiny, between the sizes of a marble and pencil eraser. Really cool stuff.

[CrabbyMom33]

Yes, 80% is better for humidity. The top layer of your substrate will tend to dry out so you can spray it with dechlorinated water to help keep it moist. Note that this will increase humidity, so if your humidity is staying pretty good then maybe only spray a couple times a week.

[HermitCrabingrid]

That's normal behaviour but 90 humidity is dealy it an grow mold and kill the crabs
70-80 is better

[wodesorel]

Further, I believe the species of crabs we have are the ones common on Caribbean and Central American beaches.

Sounds right. Purple pinchers are the most commonly offered hermit crab species here, and all pet hermits are collected wild from different places in the Caribbean. They're native from the Florida Keys down to Brazil and are even found along the Mexican coastline. You've got a claw up on the rest of us as you've actually lived in their native habitat! Replicating those conditions will make them thrive.