If memory serves me right, capture the sea is salt water only. If it is the same place I am thinking of.
Capture the Sea is about 50/50 salt and fresh. Aquatica used to be only Salt and Pond but now have expanded into fresh with emphasis still on salt. IMO Animal Island in Midlothian is the best around and its all fresh with emphasis on new and old world cichlids and predatory fish (Aro's, Bicher's etc. etc. ) with some basic community types thrown in there. They often have big fish as well because of their trade in program.