better safe than sorry a small beam and two temporary supports will cost less than $100.00, IMO money well spent. i dont think its a matter of the tank being equal to X-amount of people in a room its having the tank then forgeting the fact the people will still be there as well as the dog, kids and so on. it might not make the floor collapse but the floor does give as it is designed to and the added stress may compromise the tanks integrity.
JMO given i do not have any real structural info to go
dont forget to add the tank, stand, hood, sump etc to your weight figure
your tank, your piece of mind HTH