Generally when they raise a house, it is very well supported. It can't legally be done without conforming to the codes at the time it was raised and it should have a perimeter foundation and several post and beams at least. You should, in any house, look under the location where you want to put the aquarium and make sure their is adequate support right their. Spanning across the joists is best and even better if the joists are supported by a beam or foundation within a few feet. either direction. The biggest problem area is when you put it in the middle of a long unsupported span. It will cause sagging. If you want to put it there, there are lots of ways to make it strong, so just repost with a specific location problem and I am sure a bunch of contractors will pipe in with specifics.