not sure if i am in the right place but i will ask my questions anyway, firstly i added 4 hermit crabs to my tank 10 days ago all have died, and i have seen my arrow crab eating one. has he killed and eat them all. secondly, i added a tiger watchman goby 6 days ago have not seen him since, is it nornal for them to go in to hiding. and last one, i have a brittle worm in my tank, LFS
said it is good for the tank, but i read that they are a bad thing tho have in. what do you think.