In the picture the foremost barbs are having pale color and inside of their stomach looks dark. I have given them epsom salt bath for 3 consecutive days for 15 mins. I tried zooming on their poop and I guess I have seen very minute black dots moving in the water they were treated in. What should be my next steps to make them healthy. They seem pale and shrunk stomach but they are active and moving all over the tank and accepting food.