I have always had a problem with keepin bream or even shiners and bullheads alive in my 250gallon bait tank. They do fine for about 3-4 days and then they all start getting these sores on them and their fins deteriate off. They look like blisters. I use well water that has not been filtered before it goes in. I keep an areator and filter without a charcoal insert on them. I have tryed ick treatment from walmart but it hasnt helped. I was hoping someone could point me in the right direction. Thank you.