All, i will be trhe first to admit i know some about fish, but not alot, never had to treat for any parasites or ever had anything strange go on with them. ive kept very small populations of 3 or 4 fish most the time in most my tanks weather it be a 90gal, 40gal and so on. the point.. I have a coral beauty Angelfish that keeps pooping long stringy brown substance roughly 4 times in the last couple hours, it eats like a pig and breaths and swims normal. what could be wrong.