I have a new 39 gallon AIO. I'm moving everything from a 12 gallon into it, so I have a partial CUC, maybe 10-12 snails, 1 cleaner shrimp, 1 pep shrimp, a red mithrax crab, 1 serpent star and 1 medium brittle star. I'm going to need more snails (more cerith for sure), was thinking maybe an emerald crab. My biggest question would be about hermit crabs. Most people seem to have them but I don't. What are their benefits? Do they need new shells often (I don't want a tank full of spare hermit shells)...Any cons to keeping these guys?

Thanks!
Kris

Hermits are better at eating long hari algae than snails, other than that you don't need them. How many shells they will take in a lifetime is really up to them. At least one change for sure. Cons? Without an empty shell nearby they will take an occupied one. They may take on regardless.

You already have on mithrax crab, i wouldn't get another really they might fight, etc.... in that size tank though it wouldn't be too much of a problem. Do you have a lot of bubble algae? What is your tank facing?

I did, but the emerald crab I had took care of it. Then I got the red mithrax and my emerald "disappeared", ahem. So no bubble algae at this time. We'll see what sprouts from the new LR.

I don't have hair algae right now either, in the old tank anyway, so I will probably pass on the hermits. SO sounds like more snails will do it?

Hello Elliot on the tank it looks great Im sure your mum will get into it more when you have a full SPS system lol.

^

seems like the plan I would go with. all snail crews are really superior to those that mix in hermits or crabs. something nice about never having to wonder what the crew is up to today.

side note - emerald and ruby mithrax will kill each other as much as emeralds and emeralds, the rubys aren't more aggressive, mithrax crabs just like to kill one another.