So i would use the cups i drink out of to fill up my fish tank. since the water had to be conditioned i used aqua safe water conditioner. i put the cups in the dishwasher and washed them. would they be safe to drink out of now that there washed?

If the cup is china and has been through the dishwasher it should be just fine to drink from. Plastic cups can leach out chemicals and I would be more circumspect about them.

It is unlikely that you would have much residual chemicals from the water treatment after having been through the dishwasher cycle. I think you can use the glasses safely without worry. Good luck.