I have 6 emerald crabs that I introduced to my 450g FOWLR
tank. There is about 380 lbs of LR
in this tank.
At first these crabs were very lively and not at all timid.
After several weeks I realized that they have started to withdraw. There is no sign of them anymore. I thought they were all dead somewhere in the rocks but I caught a glimpse of one the other day.
There aren't any aggressive fish in there with them (blue angel, mono, clowns, yellow tang, foxface). There are some small snails and some dwarf blue-legged hermits.
Any thoughts on what is going on?