My Dalmation Sail fin Molly is over 5 years old and was the very first fish I ever bought. He has fathered dozen of fry which were either rehomed or moved to other tanks. He still eats a little, but the once dominate fish now lays on the bottom of the tank or sits straight up and down in the plants with little desire to move unless provoked by another fish. If it were any other fish, I would put it down. But He has earned his place in the tank and I am reluctant to do so. Is 5 years plus old for a Molly? Water parameters are fine. Water changes done weekly. No other fish affected. I have a QT but it is still in the cycling process. I don't want him to suffer, but it will be hard to say goodbye, especially if I have to do it.