Sure, no problem. Location and orientation of the tank makes a difference as well. Still good advice to try putting it as close to a load bearing wall
Yeah, you're going to have to remove the tank mates and keep just the oscar in the 55. Still not ideal, but you can make it work, by feeding excellent
I'll jump into the weight worry thread too..
I'm about to add a 55g to the bottom of my 75/90/120 Titan Eze metal stand. These stands are
*Peaks out of the corner*
Just a head's up Joe - Pacu's aren't Piranhas they look very similar but are a different species, but you are right they are herbivores. Just be aware