To Hermie or not to Hermie

[MommaFishels]

I've seen a number of posts on here by very knowledgeable people stating that they do not like hermit crabs, but I don't believe I've ever seen them explain why. For those of you that are anti-hermit crab, can you tell me why?

Up until today I had 12 hermies in my 75-gallon FOWLR, 6 red-legged and 6 dwarf blue legged. I put in a beautiful new piece of rock that was absolutely covered in purple and deep burgundy coraline algae. In less than 12 hours they had literally bombarded the piece of rock and there are numerous places where the coraline is gone and you can see the white coral skeleton that the rock is made of. I promptly removed the little buggers and plan to take them back to the LFS tomorrow. Has anyone else seen this before? I've never heard of hermies picking at and eating coraline algae.

 

[roka64]

I don't keep a lot of them in my tank, but I think they are a great addition to a clean up crew. I only have about 3 or 4 in my 55. Just make sure you have empty shells for them to grow into. The size of the shell isn't a large concern, just make sure the size of the hole on the new shells are larger than the ones they are in. They will attack snails for their shells. I have seen them going after my conch, but no dice, that conch's leg can shoot them pretty far.
I haven't noticed them eating coraline...do you have any urchins in your tank?

 

[Wizzard~Of~Ozz]

I'm still pretty new to this.. But I'll give this a shot.

Hermits are frowned on because of their homicidal tendencies. They like mugging snails for their shells, and this is comparable to mugging a person for their skin.. however, as Roka mentioned, if you have a variety of shells available for them, this is almost never a problem (I won't say that it won't happen tho)

As for your coralline question. My Astrea snails can strip the loose coraline from the surface of the rock, there is still a slight purple hue where it was, and grows back very quickly. My best guess is the coralline uses calcium carbonate as it grows, this weakens it's bond to the rock itself. they are merely picking off the loose stuff. Although personally, I've never seen my Red Scarlet's go after any coraline, or show the faintest interest in it. Coraline turns white when it dies.

On a plus side, if they are picking it off, it will float through the water and expedite the spread of this algae.

 

[MommaFishels]

No, I don't have any urchins. I know it sounds strange, but in less than 12 hours the hermits appear to have stripped a ton of coralline off of the rock. It was nice and solid purple when I put it in the tank and less than 12 hours later some patches of the purple are gone and it is now white. The hermits were all over that rock most of that 12 hours.

I never thought about them picking it off and therefore expediting the spread of it. So far in my tank, water conditions are perfect but I don't seem to be growing coralline yet, so if they pick it off it's not growing back.

 

[cmor1701d]

In a lightly fed tank hermits will go after each other and after snails. At they did in my tank. It didn't matter how many empty shells were in the tank. They always seemed to prefer one that was already inhabited. Snails only go after stuff that is dead already.

 

[Kurt_Nelson]

No, I don't have any urchins. I know it sounds strange, but in less than 12 hours the hermits appear to have stripped a ton of coralline off of the rock. It was nice and solid purple when I put it in the tank and less than 12 hours later some patches of the purple are gone and it is now white. The hermits were all over that rock most of that 12 hours.

I never thought about them picking it off and therefore expediting the spread of it. So far in my tank, water conditions are perfect but I don't seem to be growing coralline yet, so if they pick it off it's not growing back.

Did the rock go to a spot where it gets tons of light? I'd be more apt to think that the coraline died off because of the change in lighting. Probably got very little at the fish store, then got under some stronger lights in your tank, and poof... it died off - thus turning white. It doesn't take much of a change, if it's quick. Is the coraline still left in places that are shaded?... like under overhangs, etc?

I've never seen my hermits go after coraline at all - it's really not their thing. That's why I'm thinking maybe it's just the lighting that killed it, and the crabs are there just because they're cleaning off other things you can't see.

 

[melosu58]

I`ve never seen hermits mess with corraline either. I consider them an important part to the clean up crew. I have several different types and probably 30 to 40 overall.

 

[MommaFishels]

The majority of the rock is still very purple, although it is possible that the change in lighting has had some effect on it. The rock was actually under fairly intense light (MH) at the LFS. Where I am seeing the white is not uniform as if the coralline were being bleached, but more spotty. It literally looks like little bits were pulled off here and there, exposing the white underneath. In the 24 hours that the hermies have been out of the display tank, the rock looks exactly the same. So while I guess they were not eating it, it does appear that they were picking it off, or at least picking something else off and some of the coralline was coming with it.

I am going to place the blue-legged dwarf hermits back in the display tonight, but I think I'll take the red-legged hermies back to the LFS as some of them are starting to get rather large.

 

[Kurt_Nelson]

...

I am going to place the blue-legged dwarf hermits back in the display tonight, but I think I'll take the red-legged hermies back to the LFS as some of them are starting to get rather large.

I think that's a good idea, regardless of what they were doing to the coraline! The red legged ones do get large and tend to whack delicate corals with their shells.

 

[lando]

I love my hermits. They offer great celan-up and are fun to look at. I have a couple dozen scarlet hermits in my large reef and a few in my small reefs.