Yea I must be lucky because I use blackworms in almost all of my tanks(20 +) weekly and have not had one fish get sick from them. Pellets didn't cause sickness just smelly bad water unless I did a lot more water changes than I have to do now if I skipped these water changes like I sometimes do now fish would get sick. I have a whole thread in photo section on what I feed, I feed a wide variety of food weekly and I always have nightcrawlers and red worms my fish also get those regularly. I do most my feeding videos with blackworms because all the fish come out for them. My pygmy sleeper is 7 years old and has eaten blackworms the entire time without ever being sick. I rinse and clean the blackworms daily and have never had any problems with them, thanks for the info though.