Big canibalism problem

[Eclectic~Philomath]

I originally had two hermit crabs, then I got a set of four (this was last year). I then noticed that while the two had gone down to molt, they completely disappeared. Only a few claws were left. I looked up about canibalism with hermit crabs. I then tried to properly introduce two more new crabs, dipping them in salt water, and I made sure to feed up the other hermit crabs with calcium and protein, but again, after the new crabs went down to molt, they were eaten too. I gave them a gap of at least a couple of months so I could make sure they weren't deficient in anything. What I find odd is that they don't eat eachother from the same "family". I suspect this problem is down to one crab (my biggest and oldest one). I want to adopt two more crabs. Is there any way I can stop this cannibalistic behavior so I can adopt some new crabs, or should I just segregate them into two groups until after a couple of molts maybe?

Sorry for it being so long.

[hthecvt]

The crabs are being attacked while they are down molting? How deep is your substrate?

<3 Gladys, Zeus, Tango, Pico <3

[7dwarfs]

What species of hermit crabs? (If they're e's or violas you might need more substrate than you would for other species. Is your substrate at least 3x as high as your biggest crab? Do you feed calculium and protein? How big is the tank?

[CallaLily]

Hello and welcome! I'm sorry to hear you're having trouble with your hermit crabs. I think it would help us to help you better if you could answered these questions. That way we can try to get to the bottom of these attacks/deaths.

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

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?

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

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)?

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

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

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

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

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

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

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

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

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

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

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.)?

[Eclectic~Philomath]

Hi everyone! Thanks for replying!
1. Mixture 8 parts sand to 1 part Eco earth, 11.5cm/4.5 inches (3 and a bit times the height of my largest crab)

2. My gauges are in the middle of the tank temp is average 26c, humidity is 80%.

3. Ceramic hear lamp is on all the time, heat pad and heat cord in the winter.

4. Salt and fresh water, salt is fish tank salt/salt crystals I got from other crab owners. Fresh water is filtered rain water.

5. Fresh food and dry food. Sometimes I replace the fresh food every second day, but I try to replace it every day. Fresh food - meat, veggies, fruit etc. Dry food is replaced once a week or longer, depending. Examples - seeds/nuts, dried fruit, shrimp, muesli, cuttlebone, eggshell, cereals/grains, fish flakes, pellets.

6. This is my second year with the crab, and it is an Aussie.

7. He has had at least 8 healthy molts or more. He molts every 6wks, and has just gone down to molt.

8. 55g glass fish tank, some glass pieces on top (some glass panels missing, these are covered with foil, then polystyrene for insulation)

9. Hopefully three still in the tank. Both the large one and the medium one have gone down to molt, the small one is roaming around fine.

10. 10 - 15 shells at least

11. No fumes or chemicals.

12. Clean every 6 - 12 months, pick out any food lingering in the substrate, clean shells and ornaments with hot salty water, substrate is churned around and air dried (dry mountain air), sometimes ornaments switched around.

13. No sponges

14. Nothing new added.

15. When I first got the set of four crabs, they had been seriously neglected and mistreated, they looked like they hadn't molted in a while, they weren't fed properly, they had a nasty exoskeleton problem that I posted to here about before, that was a result of overly damp habitat (from previous owner). One of these four did not make it. I'm wondering if it is some form of lasting trauma.

Thanks for your help.

[wodesorel]

What makes you think they were eaten, versus just decomposing after death?

[Eclectic~Philomath]

They often disappeared so suddenly, like in the space of 3 days after getting two new hermies they just disappeared, shell left empty on the surface.I have also had a crab die molting and it stayed under the sand for quite some time and did not rot away into nothingness. It stayed well preserved. However, it was the crab that was part of the four crab "family", and it's exoskeleton was diseased.

[7dwarfs]

All your conditions seem right. I don't know, I've never lost one, and I haven't read another story like yours on here. The only thing I can think of is maybe they're bored with the dry food being the same all week? But if you're also feeding wet food, itv shouldn't make a differance. I really hope you figure it out, in the mean time, I'd keep your newbies in seperately inclosure. Are all your crabs aussie's?

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[LightFlower]

I got my first 4 PPs from the same place and have always been together. There were a couple fights at first to establish a pecking order, but otherwise, they all snuggle together in the same hut (I have 3 and they pick different ones to stay in each night :p) I got a fifth crab from Petco and bathed them all together but they just excluded and picked on him. I woke up on Christmas Eve and my second biggest crab had stolen his shell and was eating him...I guess they're kinda like a little hermit crab gang killing the outsiders! The Es I'm getting soon are being kept separately for obvious reasons!