Killer Hermit Crab

KelBell3113 · Aug 18, 2016

Hello, I'm fairly new to saltwater tanks. Mine has been up and running for around 6 weeks. Everything has been going well. Water levels are good. Snails and crabs are happy. BUT we have one red leg hermit crab that is not nice. He used to just harass some of the other critters then leave them alone. Unfortunately when I got up this morning he had killed one of my nassarius snails and took it's shell. I don't know why because I have a ton of empty shells in my tank so this wouldn't happen. We are very seriously considering returning him to our LFS. My blue hermits and emerald crab are very peaceful but this red one has been a jerk since the day we got him. He bullied a snail all the way home from the LFS the day we got him.
What should we do?

stevo01 · Aug 18, 2016

Nassarisus snails fall as prey to Hermit crabs. I believe all 20 I've had have been killed by hermits. The cerith and turbos have never been attacked. I really like the Nass snails. I'm going to buy some more, and replace everytime the head count goes to zero. IMO, they can serve as a treat for hermits and until that time clean the sand bed.

Lenny_S · Aug 18, 2016

Hermit crabs will prey on any snail they can. And especially in your case with a 6 week old system, it's not likely there is much "food" for a clean up crew. My poor nephew got a snail/hermit cleaner package and in a few months the hermits killed every snail. His tank was littered with empty snail shells.
I suggest either a snail only or hermit only cleanup crew, not a mix. I personally do snail only plus cleaner and peppermint shrimp and a couple of tiger conchs.

RobBaglieri · Aug 18, 2016

Theres not much you can do. I think that most "new" systems are over stocked with clean up crews because there isnt enough for them to eat. If the hermits are hungry, they will eat anything. You can try dropping in an algae wafer now and then. They go wild for them. I tend to lean towards keeping very small hermits and conchs.

KelBell3113 · Aug 18, 2016

Our blue hermits & emerald crab never bother the snails. We have nerite & bumblebee snails also and the red hermit leaves them alone. There's also plenty to eat. We do a little bit of flake food and algae waffers.

KelBell3113 · Aug 18, 2016

I'm waiting on my LFS to get a shipment of peppermint shrimp in. The distributor hasn't had any lately.

ahiggins · Aug 18, 2016

Do you have a sump? When I get a new batch of crabs-Ill invariably see one or two munching on coral or bullying snails or every a whole species that I didnt want in the first place! (ie I order red legs and Ill get zebras/scarlets) I just toss them into the sump. My sump stays extremely clean! They do great

KelBell3113 · Aug 18, 2016

I have a 14gallon biocube. I also noticed that my red grows constantly. He's 3 times the size he was when I bought him a month ago. Could he be a Scarlet? Is there a difference between a red leg and scarlet?

ahiggins · Aug 18, 2016

red legs crabs actually have brown legs lol and scarlets have bright red legs.
IMO, red legs are the best (for not pestering anything) but Ive seen all of them do it. Once I see it, they get plopped into the sump.

ahiggins · Aug 18, 2016

oh and red leg hermits also have bright red antennae.

KelBell3113 · Aug 18, 2016

This is my jerk crab (in his stolen shell that he killed for). I have him quarantined for the moment until I can figure out what to do with him.

KelBell3113 · Aug 18, 2016

I really like our blue leg hermits and emerald crab. They're very peaceful and never bother anybody.

Quah · Aug 18, 2016

Trust no crab. Snail only CUC all the way. Trochus and Astrea for algae control. Nassarius for waste food disposal and Cerith for general detritus / algae removal.

stevo01 · Aug 18, 2016

KelBell3113 said:
This is my jerk crab (in his stolen shell that he killed for). I have him quarantined for the moment until I can figure out what to do with him.

red leg

Salty1962 · Aug 18, 2016

Red legs are more aggressive.

saltyfilmfolks · Aug 18, 2016

It's kind of a bummer but it's the truth.
Crabs can't be trusted and shrimp are jerks.
They are after all animals.
Yup some of my favorite pets I've had have been crabs too

RobBaglieri · Aug 18, 2016

saltyfilmfolks said:
It's kind of a bummer but it's the truth.
Crabs can't be trusted and shrimp are jerks.
They are after all animals.
Yup some of my favorite pets I've had have been crabs too

I cant agree more. Shrimp ARE jerks. My banded coral ate my cleaner shrimp and terrorizes the entire neighborhood. My other cleaner shrimp ate my sexy shrimp, my peppermint shrimp steals food from coral. All of my crabs wreck stuff and make a mess. With that said, it is entertaining to watch.

najer · Aug 18, 2016

I ran my previous tank, 170 litre, invert only for about 6 months, I love my creatures!
Only crab I ever saw kill something was a scarlet hermit which I inherited.
I have at least 6 mithrax and maybe 6 hermits in 300 litres now as well as a big cuc of other creatures, google Mexican red tip hermits, no idea what the posh name is, my go to hermit when they are available, great little cleaners that don't appear to get lazy!

stevo01 · Aug 18, 2016

I suggest trying the dwarf blue leg to the OP. They seem to be the most quiet of the bunch and focus the most on algae. In my tank anyway. Regardless, it seems the Nass snails are quite a little treat for hermits.