Hermit crab aggression

[Calm Blue Ocean]

My hermit crab population consisted of four large male red legs, one female red leg, and one little female blue leg. I've had the red legs since last November and the blue leg is over two years old. The tank is 50g.

I made a rather gruesome discovery a few days ago finding one of the male red leg hermit crabs still alive in his shell but with no legs, the legs all scattered around him. I thought at the time perhaps a molt gone wrong or maybe he tangled with my pistol shrimp. Either way, a pretty crappy way to go.

Fast forward to yesterday. One of the boys had just molted and suddenly got dog piled by the other two males, and wouldn't you know, they started ripping his legs off! They got both his claws before I could get them separated.

I do have a number of extra shells in the tank but it is possible they are reaching the upper limit of the sizes I have available. The thing is, they didn't take the other crab's shell, they left him for dead with no legs, so it wouldn't seem it was necessarily shell related. They also didn't eat him so it wouldn't seem to be hunger and I do spot feed them a few times a week.

The question is, are hermits territorial and can there be issues when the males outnumber the females? These guys have grown to be quite big, using shells with 0.7" openings. I have more shells on the way just in case but I'm wondering if I might need to take one or more of these guys to the LFS if shells aren't really the issue.

For the record, Mr Crabby-No-Claws is in an acclimation box, active and climbing around on some rubble while munching on pellets and mysis. Hopefully he molts again before too long so he can have his claws back! Poor guy.

 

[blaxsun]

How big is your tank, what all do you have for livestock besides inverts and what do you all feed?

 

[Calm Blue Ocean]

How big is your tank, what all do you have for livestock besides inverts and what do you all feed?

50 gallon AIO, 2 x mocha clownfish, YWG, Midas Blenny, Pink Streaked Wrasse, Red Lined Wrasse. Feed TDO Chroma Boost Small pellets every morning and a rotating selection of frozen food in the evening (Mysis, brine, LRS, Rods). After lights out I drop a couple sinking algae or carnivore pellets to keep the peppermints happy and hopefully out of the corals!

 

[blaxsun]

Something you can try is to wrap some seaweed (I like TLF SeaVeggies green) on a small rock using a rubber band - maybe like 1/8 of a sheet. If any of your inverts (including the hermits) are being underfed they'll be all over that faster than Oprah on a baked ham. I honestly can't keep track of all my crabs anymore - I'm sure they're waging shell warfare behind the scenes.

 

[Calm Blue Ocean]

Something you can try is to wrap some seaweed (I like TLF SeaVeggies green) on a small rock using a rubber band - maybe like 1/8 of a sheet. If any of your inverts (including the hermits) are being underfed they'll be all over that faster than Oprah on a baked ham. I honestly can't keep track of all my crabs anymore - I'm sure they're waging shell warfare behind the scenes.

Sounds like a good way to put out a buffet for my clawless dude in the acclimation box, too. As they say, nature is metal.

 

[Calm Blue Ocean]

Just wanted to post an update because it's weird.

After a few days to harden up I released Crabby No-Claws back into gen pop with lots of extra shells to make sure the other crabs had no reason to bother him. I continued to spot feed him and he seemed to get along surprisingly ok.

Well, yesterday was the big day and he finally molted! But this is where it gets weird. Not only does it appear that he didn't regrow his claws (or if he did, they are very small and/or underdeveloped) but also, he's now blue. My red-legged hermit is most definitely now pale blue, right down to his eye stalks.

A bit of googling around suggests that in spite of spot feeding and him continuing to eat whatever he could pick up with his other legs there was something lacking in his diet, presumably due to his inability to pick at the rocks.

He's busy climbing around, business as usual today but it seems I might have to find something different to feed him until he hopefully regrows his claws and can go back to picking at algae.