I was feeding my rainbow fish and found that one my Australians was not interested in the food at all. Usually he is the one that goes bonkers whenever its feeding time but he just ignored the food. I thought it was weird but i decided to wait a day and see how he would do. The next day i found that he has the really skinny but long white poop coming out of him that just stays and he has yet to eat. My other fish are perfectly fine, water parameters are perfect. I looked it up and think its an internal parasite or bloating. I tried feeding peas but he does not want to eat, if it is a parasite what medication or procedure should i follow to cure him? Please help!