Sorry I havent replied to this thread sooner. The last guppy died about 3 weeks ago, about 48 hours after starting to feed crushed garlic. I stopped feeding garlic to the rest of the fish, and kept looking out for symptoms of internal parasites. None of the other fish were showing the symptoms so I decided to get 3 more female guppys about 4 days ago.
I have no quarantine tank, or the space for one, so when introducing new fish to the tank I just have to watch them for a while in the lfs and then take the risk of introducing them to my tank. My new females are now showing the same signs as the previous ones, but all the other fish are still fine. I am going to try feeding crushed garlic again, but do I have to worry about collecting the evacuated parasites or will they just die? I do 30% water changes every 3 or 4 days and vacuum the substrate every 7 days.