Killer hermit crabs

I bought red legged hermit crabs and turbo snails at my lfs and she said they would be fine together but they might take out a snail or two for a shell. I already had some of the Nassarius Snails in the tank at the time. The crabs killed every snail in my tank of both varieties, my blue legged hermit crabs, each other and my serpent star. Is this normal?!? I expected them to eat the Diatoms that are quickly covering my whole tank and they haven't done anything but eat everyone else in the tank, everyday I scoop out chunks of something dead they destroyed.

 

Hermits, like nearly all crab species, are opportunistic omnivores. If they're not getting enough meat in their diet, yes, it is perfectly normal for them to kill for it.

BTW, your LFS should not have sold you anything to feed on Diatoms; they disappear on their own, then your CuC is left with nothing to eat. They are not little vacuum cleaners, they are live creatures with a huge appetite.

 

Suggestions?

So was taking the crabs back a rash decision? Are just snails going to be enough as my cuc or should I get something else? I don't have much for fish but I do have two peppermint shrimp.

 

Nope, not at all.

Yes. Quite a few folks only keep a small number of snails.

 

I try not to mix hermits with snails for the reasons Mr. B stated however.I guarantee your red legs did NOT kill your blue legs or serpent star.What you were probably witnessing was the crabs doing there job of cleaning up dead and dieing animals. You say you have diatoms??This suggests a new system.If that is the case the animals could have died for starvation,or unstable parameters.Please test and list them.

 

1 Scooter Blenny
1 Os. Clown
1 Spotted Mandarin
2 Neon Golbies
2 Peppermint Shrimp

They definitely killed the snails and crabs. I saw countless times where a blue legged would crawl by and the red legged would flip them over and eat them. I've seen them do it to each other as well. Every fish in there is very peaceful and playful, there's no way any of them hurt somebody. As for the serpent, we only had him two days and every time I looked in there they were eating his legs, he had chunks missing everywhere. The tank is a little over three months and my water has been spot on every monday when I test it for the last two months. Am: 0, Nitrates: 0, Nitrites: 0, pH 8.2-8.4, Sal 1.023. I'm not sure if it's even diatoms that's in there to be honest. My lfs said the brown that quickly spread across my rocks is that.

 

Yup,it could be that the red legs were simply the hardiest and the last to survive.

 

Well thats shocking.I have mixed red and blue leg hermits for years.The blues always seemed to bully the red legs.
Please post a pic of the red legs if you can.

 

I already took them back. I to be honest am not positive they were red legged. They were mostly brown with the tips of their legs and claws red but my lfs swore that's what they were. But I never saw them doing anything with the brown covering my rocks, just hunting for snails, blue legged and each other. I tried feeding them the brine shrimp when I fed the mandarin to stop them from the hunting but it didn't deter them at all.

 

No crabs of any sort in my reef tank. Tired of them bullying snails and nipping at corals when bored or hungry. I found myself having to feed the crabs to keep them off my other critters, which is directly against my reason for them being there in the first place.