Well it turns out his poop is white and stringy. What should I do?
I use prazipro for internal parasite
Per another site, "Praziquantel is a dewormer primarily, whereas metronidazole is a rather broad protozoacide." This concurs with some other research I've done.
It's a hard balance between being sure what disease your fish has vs. treating too soon with the wrong thing, also between the sentimental and monetary value of the fish vs. cost of meds.
I made a mistake on this a while back treating for ich when it was really a fungus, and the treatments were opposite (high heat vs. lower the temp, plus which meds), so I lost most of a tank of fish.
If at all possible, as suggested earlier move the sick fish into a separate tank and treat in there so you don't waste medicine or stress out the other fish. That way if your diagnosis was wrong you only lose one fish instead of all of them.
Hope it all turns out OK.