1500 gallon for a mbu, and a dozen or so cichlids of some sort or Dats
1000 gallon blue xback aro, blood red aro, 3 sting rays, pbass, TSN, Tigrinus cat, 2 ST, 2IT, 1 NTT
and the most realistic, just waiting for the fish:
40 gallon long with a red congo puffer