Safe to draw a dot (using a Sharpie marker) on shell?

[CrabbyMommy2017]

Good Morning,

I think I already know the answer to this question, but I wanted to be sure. I'm having trouble telling my crabs apart. Three out of the five have chosen shells that are almost exactly alike (green Turbo). I'm having trouble with one of my crabs being aggressive. The aggressive crab, Boop, is actually in a different kind of shell, so he is easy to tell apart. I have feared for the other crabs safety and placed Boop in a separate isolation tank for now.

I would like to put him back in the main tank with the other four to see who exactly he gets along with. If I could find out who Boop actually does get along with, then I could split the crabs up so that both tanks have at least two crabs. But since three out of the five have chosen shells that are almost exactly alike, and those three are almost all the exact same size, it's hard to tell.

I was thinking about taking a Sharpie marker and drawing one dot on the outside of the shell of one crab, two dots on another crab's shell, three dots on the other crab's shell. This doesn't seem like it would cause that much harm. But it still seems a bit iffy. I would welcome any other ideas as to how I can tell the crabs apart from each other. The Sharpie dot idea seems like it could possibly be harmful, but then I'm not entirely sure since it is the shell itself and not a part of the crabs natural anatomy. Sharpies are non-toxic, after all, and I've seen many a hermit crab in a painted shell (although I don't use painted shells myself). Any suggestions and feedback welcome and appreciated.

Thanks in Advance,
CrabbyMommy2017

[GotButterflies]

I would think it would NOT be safe. Sharpies are non toxic to humans. Sharpies have strong odors to them, and I think it could be harmful to their modified gills. I always go by the better safe than sorry rule.


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[CrabbyMommy2017]

Here is the emergency template


1. What kind of substrate is used in your tank and how deep is it?

Play sand coconut fiber mixture 6 inches deep

2. Do you have gauges in the tank to measure temperature and humidity? If so, where are they located and what temperature and humidity do they usually read?

Temperature and humidity gauge in one, digital, located in the middle of the tank stuck to the glass with a suction cup, usually reads 82 degrees and 78 to 82% humidity

3. Is a heat source used in the tank? If so, what?

Ultra therm uth mounted to the outside back glass of the tank above the substrate level. It is the full size of the 55 gallon tank.

4. What types of water are available (fresh or salt) and how is the water treated (what brands of dechlorinator or salt mix and what ratio is used to mix it)?

Fresh water bowl with bubbler, saltwater bowl, treated with instant ocean. I forget the brand name but I use the aquarium grade fish products to dechlorinate as well as stress coat

5. What kinds of food do you feed and how often is it replaced?

Food replaced every 2 to 3 days or as needed. A variety of fresh fruits and vegetables. Hermit crab safe pellet food. Dried crickets and krill.

6. How long have you had the crab and what species is it, if known?

Four of them, including the aggressive one, since February of this year when we first set up the tank. One was recently added last week. The recently added one was in isolation tank for 24 hours before adding to the main tank.

7. Has your crab molted, and how long ago did it happen?

I believe two out of the five, possibly three, have completed molting. They are all tunneling quite a bit so it's hard to tell who has molted and who was just tunneling.

8. What type of housing are the crabs kept in, what size is it and what kind of lid is on the housing?

55 gallon tank with 4 plexiglass lid panels

9. How many crabs are in the tank and about how large are they?

5 all of them are small to medium in size

10. How many extra shells are usually kept in the tank, if any?

It's hard to tell now since they have been tunneling and buried several of them. There are at least 10 but possibly 15. I can't remember.

11. Have there been any fumes or chemicals near the crabitat recently?

No

12. How often do you clean the tank and how?

Spot clean up for crab poop and food debris

13. Are sponges used in the water dish? If so, how are they cleaned?

No

14. Has anything new been added to your crabitat recently?

One new crab

15. Is there any other information you would like to share that might be helpful (anything that is regularly part of your crab care, playtime, bathing, etc.)?

Forgot to mention that there is a colony of roly-poly bugs living inside the tank as well. I estimate there are anywhere from 100 to 300 of them currently

16. Please describe the emergency situation in detail.

I need to separate out the aggressive crab into his own separate tank. I fear that he has killed at least one crab who is molting and possibly two others. But I'm not sure if they're just still molting and haven't come up yet. I have seen him attack other crabs and he is currently in the isolation tank by his self.

[aussieJJDude]

Have you thought of mashing up berries and using the resulting paste to stain the shells? Would work well and eventually come off...

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[CrabbyMommy2017]

@aussieJJDude

That's genius! I've got some blueberries in the fridge that I could use for that.

[Hermias_mom]

Here is the emergency template

5. What kinds of food do you feed and how often is it replaced?

Food replaced every 2 to 3 days or as needed. A variety of fresh fruits and vegetables. Hermit crab safe pellet food. Dried crickets and krill.

10. How many extra shells are usually kept in the tank, if any?

It's hard to tell now since they have been tunneling and buried several of them. There are at least 10 but possibly 15. I can't remember.

So, this isn't about marking shells per se, but I'm trying to address your root cause. You probably know all this, but maybe I'll have an idea that you haven't thought of yet that could help. If one crab is displaying agression, usually it's due to establishing dominance, trying to fix his nutrient deficiencies, or wanting someone else's shell. Sometimes it can be a male/female thing.

Maybe I'm reading it wrong, but it sounds like you have only 10-15 extra shells total in your tank. For 5 crabs, I'd recommend at least 25 shells total (at least 5 per crab in their size and a bit larger). If you select these shells so that each crab has at least five shells of a preferred type in his own size, and five shells that are a bit bigger (like 1/8" or so), then that should help if your agressive crab is being agressive because he wants another crab's shell. Also, if the shells are buried in the sub, the crabs usually won't think about them as an option. Sitting on top of the sub is fine, but often if sand gets into them, they could be less desirable to the crabs, since the crab will have to clean them first. I'd recommend rinsing out your shells, boiling in dechlorinated water, rinsing again in dechlorinated water to remove whatever debris the cavitation from the boiling loosened, then dip the shells in saltwater and air dry. That will get most impacted dirt out and put a layer of dried salt on the outside and inside of the shell (EDIT: what I meant was, as the saltwater evaporates off of the shell, a very, very thin layer of salt is left behind. Just dip shells in saltwater, dump the water out, and then lay out to air-dry. Think there was some confusion on my meaning here.). Crabs love to eat the salt out of a shell - it seems to help them be more interested in the shells (you almost can't see any salt when they do this). I'd try storing your shells in a plastic basket/shower caddy, or somewhere that they can't easily get dirty and dragged off. Having a few they can play with and bury in the sub is fine, but personally, I'd try segregating most of the shells to help them stay clean and available for the crabs that want to check them out and change.

If your crab is being agressive due to nutrient deficiencies (he's really trying to eat the other crab), you might try expanding your protein selection and variety, and increasing the frequency at which you offer it. Might also try different types of exoskeleton. Also, sometimes they'll eat something that's dried that they wouldn't eat fresh, so you may try offering more dried ground up bugs or similar. Also take a look at the calcium sources and see if you can increase the variety there. Again, crabs will eat stuff dried and crushed that they won't eat fresh, sometimes. Check out the food pyramid and the rest of Kilimanjaro's post for good ideas, if you haven't already. http://www.hermitcrabassociation.com/ph ... 25&t=92554

Best of luck!

[wodesorel]

Marking shells rarely works for long - they will swap shells between each other and well as change on a whim. Tracking shells is no guarantee!

[GotButterflies]

I agree that you need more shells. I do not agree with layering shells in salt. The pure salt can possibly burn their abdomens. To entice shell changes, after boiling in dechlorinated freshwater, simply dip in dechlorinated marine saltwater, or just dip in dechlorinated marine saltwater period. When I first started crabbing I did not have shell shops. Shells constantly got buried and dirty. I highly recommend shell shops- putting shells in a second level in the tank. They still get a little sandy, but nothing like when they are on the substrate. The HCA recommends 3-5 shells per crab, but I recommend more. Never hurts to have more shells! This way you can switch them out constantly.

I thought about several things that are natural dyes, but they could attract a crab to want to taste them! Lol- hibiscus flowers, currant, etc

They are going to have to establish a pecking order with the new crab. As long as the new crab was dipped in the freshwater of the crabitat, and nobody is pinching- losing legs or being forced from shells, I would keep a close eye on it.

It never hurts to have more protein. I know you are crabbing on a budget- and I admire everything you have done! Even if you can provide them with a pinch of whatever meat you are eating for dinner before you season it- that will help!


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[CrabbyMommy2017]

Thanks to all for your advice here. Im going to have to do an overhaul (ugh, again), because we have so many climbing branches there's no room for a shell shop. Ive been trying to come up with some sort of second level that looks all natural, but still has a clear bottom so light passes through. Im thinking cocofiber mat around the sides of a suction cup shower corner shelf thingy might work.

My husband and i constructed a second level on one end, but its so dark under there. Im trying to make the tank look as natural as possible. I know the crabs probably dont care, but i do. The tank is in the first room of our home and there's kind of already a nature inspired meditation theme going on with the decor of that room.

Ive got more shells i can add, probably at least 25, but with 2-3 crabs still underground i guess i will have to wait to dig out the shells already in the tank. I will make sure and clean them all, as instructed, when the time comes.

The agressive crab is in the iso tank now with 5 extra shells. He has been there for a few days and not changed shells. He has actually been trying to break out of there, climbing up to the ceiling of the tank and hanging from the edges and thumb holes of the plexi glass lid panels.

Today is my day for the grocery store and errands, and i got some birthday money yesterday, which my husband said i am not allowed to spend on homeschool stuff, so im going to scope out some second level construction materials that will fit the crabs' needs (for a shell shop) and my tastes (all natural appearance).

I had thought that staining the shells with fruit or vegetable juice might be a good idea but a very good point was raised here that that might create even more problems with the markings making the shell more sought-after.

For now I am just going to keep the aggressive crab in isolation. Better safe than sorry. The crab that he was attacking last time (when I removed him) did seem to have an injury at one of the joints of its leg. I may be wrong about that. That may have already been there or it might just be the way that crab's leg is shaped. At any rate I'm still worried that the aggressive crab had gone under and killed two that are still under the substrate. I havent smelled anything bad in there, and its still been less than a month since they went down, so here's hoping that's not the case. Still, i think its better to keep him separated until i see all of the other 4 above ground and know that they are ok.

Thanks for yalls advice and feedback. As always, its appreciated and welcome.

CrabbyMommy2017

[LadyJinglyJones]

If you keep a dish of dried whatever-you-stain-a-shell-with in the tat, the crabs will cease to regard it as a delectable to be taken advantage of. Sometimes they probably won't care for it at all - familiarity breeds contempt &cetera.