I just upgrading my fish in my 5.5 gaalon into a bigger tank, I have 6 freshwatertanks and was thinking of switching it up with a small nano tank but my question is what would I need to buy, I have a heater tank glass top and a hang on filter, I was think of just live rock a saltwater hermit crab and MAYBE a small 3/4inch blue dmsel, and is this even posible?