Unfortuntaly the ones that I've found to be best are out of the way a bit, being either in Doral (out west on 25th st. and between the 826 and 836) or down on US1 (same as Dixie Hwy and spilldown from 95) and 142nd st. but those are down way south of the Biscane bridge that we're going to take out to Seaquarium.
The closest store that I know of is going to be either Gables Aquariums (an okay store, they've got a lot of livestock, just south of SW 80th st on the left, where there is a building that looks like a miami subs, but is being transformed into a bank I think?).
Or the 2 or 3 stores out on Bird Rd. You would take 95 down to Bird Road/40th st., maybe the 4th or so light after the spilloff onto US1. There is Exotic Aquariums and 2 other stores. Exotic Aquariums is pretty sweet. They're all out west a bit though, right before you hit the 826 north/south on the right hand side.
There are a few choices, most of the stores are pretty sweet.