Bammmf!
Someone spent too much time in front of the TV, or either is the proud owner of The Official Batman Onomatopoeia Dictionary.
Have we hijacked this thread long enough, or should we keep on going?
12 inch joists with a 90 gallon tank running perpendicular to said joists, with said tank also situated parallel to the foundation wall, and in close proximity thereof, will easily support said tank. DO IT!