I have 5 discus one of which has white stringy poop for about 2 weeks. He's been turning dark and hiding. Now not eating. I first treated with api general cure for parasites and fed metro treated flakes and pellets for five days. Fish looked better but still had stringy white poop. Was advised to treat good with epsom salt mixed with water and prazi pro which I have done for another 5 days and he is still dark and hiding on and off and still having white stingy poop. Ive done 70% water changes between treatments and removed carbon during treatment water is 84 degrees and water parameters are good. I've also used salt although recomendations for salt are mixed with discus. Please can someone help. I truly don't know what else to do and I'm afraid of him getting too far gone to get well!