Slowly loosing hermits - why?

[msalganik]

First non-picture post here. We've had our RSM250 up and running for nearly 11 months now. Tank is well established and we've got a mix of LPS/SPS with a few softies as well as a number of fish - everyone is pretty happy. We do have 1 large skunk cleaner shrimp, 1 peppermint (hides all the time) and 1 fire shrimp. They are doing fine and molt regularly.

That said we have had a slow but steady stream of hermits that we keep finding out of their shells and dead in the substrate. We started out with 20-25 and I'm now at the point of needing to pick up more to replenish the cleanup crew. Before I do though I want to make sure I fix whatever is killing them. We don't have much algea growing in our tank but there is plenty leftovers when we feed the fish (twice a day) and we feed a wide variety (reef frenzy, chopped clams, blackworms, supplement with fish eggs and mixed algea in a tang feeder). Any ideas on why we're loosing them?

 

[Tahoe61]

Are there larger shells for the hermits to move into?
Are there fish types in the tank that will pick off hermits, such as Triggers?
Are there larger hermit types killing off the smaller types?

 

[msalganik]

Are there larger shells for the hermits to move into?
Are there fish types in the tank that will pick off hermits, such as Triggers?
Are there larger hermit types killing off the smaller types?

Thanks for the reply!

- there are additional shells though I suppose I could have more (feels like many have slowly disappeared, don't know where to)

- no triggers. Fish in the tank are yellow and powder blue tangs, melanurus wrasse, fire fish, scooter blennie, cleaner wrasse, oscellaris clown and longnose hawkfish. Besides the shrimp listed the only other inverts are 2 sand sifting starfish, a black brittle star and two fragments of a BTA (that's a mystery of its own). I haven't seen anyone actively go after the hermits.

- the only hermits we have are either orange or blue legged. Early on we did have one that was large and clearly picking on the rest. We got rid of him. Since then I haven't seen any obvious bullying.

Any other ideas?

 

[SeahorseKeeper]

If I had to venture a guess, I would suspect that the longnose hawkfish might be the culprit.

 

[Roboson]

Possible fish culprit. I'm not sure about that. If it's not the fish here's what may be happening:

Do you have any macro in your tank? Hermits tend to need some green in their diet. If they're not getting a good diet, it could cause them to become easy prey for other hermits or fish.

Also if you don't have enough iodine in your water, they may not be able to molt properly. This can cause horrible horrible things to happen to hermits.

Either of these things could be happening separately or in addition to fish predation.

 

[msalganik]

Thanks for both of your suggestions! When they died, i've found them out of their shell, which I wouldn't expect if they were being preyed upon by a fish. That said, our rock is fairly bare and just starting to get some "fuzz" back after we got rid of our halloween urchin (bulldozed one too many frags). We keep a tang feeder regularly stocked for the fish but it's too high up for the hermits to get at so that may be part of the problem. We also use to get our saltwater premixed from our LFS who uses regular IO. I've finally had enough of having to supplement like crazy (their water tested 1050ppm Mg+ !!!) so I've started making my own sw using RedSea Coral Pro salt mix - hopefully that'll help with any trace element deficiencies. I've got a dozen new hermits in the tank and so far (48hrs) they look happy.