GBRU is correct....it may cost you 300...but it buys insurance for peace of mind...your father can do the work...
With the above said...LOL.... I have a 900# safe going in on the third floor and a 10,000# aquarium going in on the 2nd floor all in the next 2 months...So I have spent some considerable time on this... The safe is HEAVIER than the tank is.....why?, because the safe is 152# per sq foot and the tank is 124# per sq foot..... you can google how to figure these numbers out...very easy to do, basically foot print in inches or feet divided by weight.
some random thoughts...
Wood floors or any floor isnt really part of the consideration...if you are going to put a tank on carpet, tile, etc... they are going to have plywood underneath them so technically they are also wood floors.... and there are ways to keeping the stand from scratching the nice wood floors but different topic...
What I would suspect you will end up doing....is sistering DEMONTIONIAL LUMBER (not plywood) against the joists underneath and then boxing them in...look up sistering and boxing....you father should be able to do both rather easily if he has access...I would also make the sisters as long as possible not just under the tank..... THEN google beam calculator and put your numbers in.... So you may end up say putting a 2x8 or 2x10 underneath the tank with concrete footers...as long as the footers are poured correctly I think you will be fine.
also remember when working with wood....Width of the wood may be more important than thickness..... 2 doubled up 2x4s are not nearly as strong as 1 2x8 for deflection......
Not to say anything about posts here or anywhere else...but just because someone else did something does not mean anything to your situation.... they may have tanks against load bearing walls, in apartment that were built with concrete floors on all levels...etc, etc, etc.... My situations are even different, I have a "shear" issue on the safe but a deflection issue for the tank....I have to tackle them differently... also the old "2 of my 200# friends standing close together on a floor has not caused a problem" thought doesnt work either....they will not be standing there group hugging for 20 years as a live load....