it is funny, like mentioned, teenagers are not necesarily the prob, there are many mature teens here and many immature adults, so i agree with not going to the age issue, it has been said before, and you cannot judge a person by age
now, for the other issue, do what you want with your tank, yes, but i belive strongly that fish are like any other creature we bring home, we SHOULD adopt them and not borrow them, meaninig when we bring them home, we should provide them with the best possssible care and all(for life)
just my opinion, but we should be responsible aquariists,not self centered immature heathens, it is our responsibility to care for any animal we bring home
oh, and yes ithat is way too much for a 75, you really should re consider your staocking options, IMO, some good advice has already been given there