Opinions on Halloween Hermit crabs

[antigonus]

I am considering getting a Halloween hermit crab, both because I love the way they look and because according to Liveaquaria at least they can eat Cyanobacteria, a lot of places say they're reef safe, but I have also read some accounts of them being aggressive. I have a conch I don't want to risk losing to an aggressive crab. What are peoples' opinions of Halloween hermit crabs?  Do you generally consider them benign, or not worth the risk? 

[Nano sapiens]

The aggressiveness moniker is because the hobby has had the same 'Halloween Hermit Crab' name for two very different hermit crabs. 

 

The more aggressive one is this guy (comes in this orange and also a blue form):

 

 

 

The one that most people know nowadays as the 'Halloween Hermit Crab':

 

 

A bit larger than you're typical CUC reef hermit...

 

I've had this one for a few weeks now in my 12g and so far it's been a model CUC citizen.  The one I have is a juvenile of about 1", so the same size as an adult Red-Legged hermit.  It even snacks on colonial hydroids, which is awesome!  They are a bit slow and clumsy, but that's part of their charm 😊

 

These Halloweens have a body specially designed for cone shells and other similarly long and narrow opening shells.  Potentially, this type of hermit crab could go after your conch if it is the right size for it to use it's shell and no other suitable cone shells were present.  If you do get one, make sure you have a few extra larger cone shells available for it when it molts (you can get extras from Reef Cleaners):

 

https://www.reefcleaners.org/aquarium-store/tank-cleaners/6-empty-cone-shells-detail

[antigonus]

50 minutes ago, Nano sapiens said:

The aggressiveness moniker is because the hobby has had the same 'Halloween Hermit Crab' name for two very different hermit crabs. 

 

The more aggressive one is this guy (comes in this orange and also a blue form):

 

 

 

The one that most people know nowadays as the 'Halloween Hermit Crab':

 

 

A bit larger than you're typical CUC reef hermit...

 

I've had this one for a few weeks now in my 12g and so far it's been a model CUC citizen.  The one I have is a juvenile of about 1", so the same size as an adult Red-Legged hermit.  It even snacks on colonial hydroids, which is awesome!  They are a bit slow and clumsy, but that's part of their charm 😊

 

These Halloweens have a body specially designed for cone shells and other similarly long and narrow opening shells.  Potentially, this type of hermit crab could go after your conch if it is the right size for it to use it's shell and no other suitable cone shells were present.  If you do get one, make sure you have a few extra larger cone shells available for it when it molts (you can get extras from Reef Cleaners):

 

https://www.reefcleaners.org/aquarium-store/tank-cleaners/6-empty-cone-shells-detail

Thanks for the link! I've been looking for shells!

[mndfreeze]

My experience with hermits is any time there is a snail with their preferred type of shell, it's always at risk.  Red legged and blue tricolors prefer cerith style shells.  I've never once had them kill any other snail than my ceriths.  I have another hermit of unknown ID that seems to prefer astrea/trochus style shells.  ####er has killed 3 of them so far.

 

IMO, if you like your conch, I would avoid getting a hermit that specializes in cone/conch shells.  You are just asking for it to become a snack at some point.

[antigonus]

17 hours ago, mndfreeze said:

My experience with hermits is any time there is a snail with their preferred type of shell, it's always at risk.  Red legged and blue tricolors prefer cerith style shells.  I've never once had them kill any other snail than my ceriths.  I have another hermit of unknown ID that seems to prefer astrea/trochus style shells.  ####er has killed 3 of them so far.

 

IMO, if you like your conch, I would avoid getting a hermit that specializes in cone/conch shells.  You are just asking for it to become a snack at some point.

Fair point, I've had good luck with mine probably just because I've never kept too many, (generally under seven), they're too small and slow to really go after my Trochus and Nassarius snails.

 

It might be a better idea just to get some more Nassarius snails to stir up the sand bed.