Something eating hermit crabs and turbos

[jbing27]

I'm new to this hobby. My 24 gallon Nano Cube has been populated for about 3 weeks since it finished cycling. Most of what is in the tank came from a 20 gallon established tank, so I have some nice live rock with pulsing xenas, mushrooms, a few brown polyps and coraline. I have a small white damsel, a true perc (1 1/2"), an orange banded goby, and a small peppermint shrimp. I also put in 6 turbo snails, and 9 red legged hermit crabs. 2 of the snails have been killed and partially eaten before I found and removed them. Yesterday I found 2 partially eaten hermits, and today I just found another. I observe bristleworms protruding from the rock and have managed to catch and dispose of a couple on occasion. I am at a complete loss as to the cause of my invertibrates getting knocked off one at a time. That little damsel is pretty aggressive and is always posturing at the goby and clown, but he's real small and they stand up to him and back him down. Has anyone ever heard of a damsel killing snails and hermits? The only other suspect would be the bristleworms, but they are not that big,and they are the white kind--not fireworms. Any insight would really be appreciated.

 

[Kurt_Nelson]

Totally a guess, but I'd say your hermits are killing your snails, and your dead hermits are actually just the molts from the hermits. OR, if you're absolutely positive they're not molts, the crabs are killing the crabs.

 

[jbing27]

They are not molts. I am finding empty shells. The entire front end of the crab is intact. These are small Carribean red leggers. I've seen Zebras do this. I have 2 sons that have been in the hobby for a while. We bought 18 crabs and put 6 of them in my tank. He's not having these issues in his tank. I really doubt its the crabs. I guess its possible there was one psycho in my group.

 

[thincat]

I would suggest that you add empty snail shell to keep the possible aggression for larger shells among the hermits. It is not uncommon as Kust stated that the hermits are killing both you snails and hermits for their shells. Your friends tank may have a slower grow rate amoung the hermits and is not seeing any aggression "yet".

 

[thincat]

An other thought is that you might have a mantis or pistol shrimp in the tank. Do you hear a popping sound?

 

[jbing27]

I have a dozen or so different size shells to accomodate the crabs. No pistol shrimp or mantis.

 

[Kurt_Nelson]

Even though you've ruled out the crabs, just for purely information purposes, even with extra shells crabs will still kill snails and other crabs just to "try on" their shells. I watched one of my crabs yank out another hermit, kill it, and move in to its shell. The very next day, the killer crab was back in its original shell leaving the other one empty. I think that's pretty common for the little devils. There's a reason I only have a couple in my tank now days!

 

[jbing27]

Yeah Kurt, I think you may be right. After repeatedly observing the goings on in the tank I noticed a larger hermit sporting one of the turbo snail shells. I didn't realize I had one big enough to handle a shell that large and heavy. Sure enough a short while later I caught him on top of a crab half his size trying to evict him his small shell. I don't begin to understand the thought process of a hermit crab, but given the size difference, it appears he's aquired a taste for red leggers and snails. I sequestered him to private quarters. This afternoon he's going to a local shop that will take in these Jeffry Dahlmer types. Thanks for your input. I appreciate it.

 

[melisssaparker46]

i think you should not mix them in one aquarium.