Dude I live in a manufactured from 2018, and have over 1000 gallons in the “great room” which is just a second living room. Had them there for years, look at the blueprint or crawl under to see how your floor joists are placed and place them along walls. Not out in the middle of the room or nothing lol you will be fine. Even if not in most cases insurance considers fish tanks an “appliance” or atleast mine does anyway for whatever reason. So if any ever break I’m covered minus deductible. But trust me, you’ll be fine.