I know this probably sounds silly, but I never observe my fish poo! I have 4 male better fish who have quite the appetite. I know they are going because they continue to eat, they do not show signs of being ill from parasites because they are all full of personality. It is also important to note that they are in heated, filtered 5 gal cycled tanks with regular water changes-- half of the tanks are planted with substrate and the other two are bare bottom with hide outs and free floating plants. They do not appear bloated regularly and when they occasionally do I fast them for a day and they seem fine. Should I be concerned and treat the tanks for parasites or let them be? I also find it odd that it happens to all of the tanks since I am very sanitary, could there be a possibility of cross contamination. I have also noticed that some small snails have hitched a ride form some plants-- could they be decomposing the solid waste? Thank you all!