So i'm getting a 40 gal tank... Only had goldfish before.... Want to get a oscar, red devil, cichlids, parrot, or terror...Any advice??? I need gravel and some plants for the inside, any recommendations?? Also saw some Aussie Crabs at LFS, are they compatible with the types of fish listed above...want to get the fish tank going before the end of the weekend so i can get some fish in there in a few weeks..PLEASE HELP A NEWB!! All advice and suggestions welcomed and needed.