My betta is in a 10 gallon. Ammonia=0 nitrites=0 nitrates=5 ppm, ph is 7. A betta previously in the tank had it (camallanus not noticeable until long after I bought it). He had the white poop, worm hanging out the anus, and was spitting pellets back out. I followed what I thought was the treatment plan (one levamisole treatment for 3 days, then wait three weeks and redose) and afterwards concluded that the tank was treated. The fish was now eating, having normal poop, and the worms were expelled. That fish died for reasons unrelated to camallanus. The person I left in charge of the fish when I went away (who knows how to take care of fish and who I trusted) did not keep their word. I was upset and mourned for the fish because I cared about it so much (rip bubbles). Anyways, thinking the tank was still healthy I added amother betta (this time not making that same mistake I promise). Everything was fine until he started having the worm sticking out the anus and the difficulty with eating. What is odd is that he has normal poop. I went on another forum and they said to have two consecutive dosing periods of levamisole, wait two weeks, then do it again. I finished dosing twice and I'm in the two week waiting period. He expelled worms during the two dosings, however still has difficulty eating. I was wondering if an alternate kind of food would help.