I have a bio-cube 14 tank that was given to me. it's about 8 months old and has live rock, 3 snails, and a hermit crab. it had a peppermint shrimp, but that recently died. i want to get it to the point where i can add a couple fish. there has never been a water change or anything like that. i am completely clueless as to where i need to start. what comes first? i've never had a salt water fish tank before, so have no idea what steps need to be taken. any help would be appreciated, thanks!!