This is gonna be my very first thread ... and it is at the fish disease section. Sometimes I see one of clownfish has white stringy poop. Sometime it has more than one string and it has greenish color too, is it because it ate algae in the tank? He is very active, and eat like a pig. I have him for more than 1 year. I have 3 fish in my 29 g tank: a pair of clownfish and green chromis. All of my fish eat well and active. If it is internal parasite, is it contagious to other fish? Do I need to treat all of my 3 fish? What medication should I use? I do have PraziPro and General Cure in my hand, but not sure which one to threat with. I don't even know if it is internal parasite at all. I didn't treat them with PraziPro when I first got all 3 of those fish, which was more than one a year ago. Please help.