Hi fish boy, sounds like they are just stressed, I also winter my pond fish indoors, you have to keep in mind that pond fish are generally accustomed to higher levels of ammonia, nitrite and nitrate, because we don't really do water changes on there ponds. Sudden changes in these levels can really stress your fish.i would cut back to about 25% water changes!once a week. Also, if the garage temps are below 65 degrees, I would reduce their feeding schedule to once every other day. This will cut down on the amount of waste they put out and help with water quality. Hope this helps.