Not to sound like the hulk, but simple physics and carefully planning, you can move more than you think. I just lifted a 125 up on a 4 foot tall platform using cribbage.
Gallon wise the IBC tote will work but consider all the necessaries like heat, light, and filtration.
Yes its just that 250G is heavy. I currently was moving my 140 myself and that thing was heavy. I'm not that strong about 5'5 128 pound. Having my arowana in it right now. That's why I wanna see if there is enough space for him until he is fully grown.