Yeah they are pretty mean. A few of them confiscated/murdered a few snails. At least I get to see them the only time i see my scarlet is at night. It could be another molt depending how much there is to eat they can grow/molt quite often. But if someone already moved into his shell that doesn't sound too good for him. I've had mine for about 7 months now.
Your temp seems to be a bit near the high end. To feed algae strips/nori just put one end under a small rock or stick it in the sand. That's what I've been doing too bad my clown doesn't know what to do with it.
