Don't let people judge you, they don't know you and don't know what your going through.
Talk to your dad and show him the flood alarm and tell him how important this is to you. If he still doesn't allow it, then make sure that they are healthy and not cramped in the 20 gal. tanks, If they are then move them to the basement until you start your own life. congrats to the wedding and I hope your little sister gets better.