OK
1-This thread isn't even about the 30gal with pacu. That's for another time.
2-No, a 3in Oscar wont grow out of a tank over night. But the current stock of the 60gal hex with the current filtration and the current feeding regiment IS NOT GOOD. There are things that he can do now to help the situation.
a)Get rid of the gar. It's not going to work with the Oscars anyway.
b)Get a filter that can handle the Oscars
c)Reduce the amount of feedings
d)Stop using live feeders
e)Start 50% waterchanges weekly to prevent disease
All of the above will keep the tank HEALTHY for a few months while looking for a new tank and cycling it properly before putting them in the new tank.
3-Yeah some people have been jerks on here and that's unfortunate. But all in all, good advice has been made. Good advice that has been attacked and labeled flaming when all it was was stating facts and experience. That is what this forum was made for, sharing these things.
4-You don't have to be rich to own fish but if all you can afford is a 29gal (theres no problem at all with that) then stock it accordingly. Don't get pissed because you bought pacu and are just now realizing that your fish store and public aquariums won't take them back. There is a reason for that. As previously stated, a pair of Pacu will outgrow a 600gal tank. And no thats not a rediculous size tank because or their size and waste output.
Everything that needs to be said has been said. Peanut Power was kind enough to leave the thread open so we could right the wrongs. I thought it would have been closed by now. I think we should stop repeating ourselves at this point and see if the OP has anymore questions about HIS tank that we can help with.
I think thats all I wanted to say. Think productive everyone!