I have a guppy/ molly colony. A few of my older fish looked like they got guppy wasting disease. They got skinny then eventualy stopped swimming and died. But their poop never turned white and stringy. All my younger/ smaller fish show no signs. I still have 2 fish looking skinny, they are eating normal and pooping normal. The fish affected have all been. Around 2 years. Should i treat my whole tank for internal parasites or assume its just old age? If its just old age is there anything i could be doing to prevent this?
