This is my experience with IP's (internal parasites) and puffers. 99% of all puffers are wild caught. There are very few puffers that will breed in captivity. With that being said you "must" treat any puffer you purchase for IP's.

If you are thinking about buying a puffer make sure you have a fully cycled tank. Ammonia and Nitrites are highly toxic to puffers. Do your research before you buy. What size tank does my
puffer need, is the puffer I want freshwater or brackish water?...

This is a first hand account of how one of our members (Zulaab) successfully killed Camallanus worms using Fenbendazole (sold as Safeguard Canine Dewormer).

---

First, make sure your fish is willing to eat. If not, get it used to bloodworms (you will need bloodworms to feed the fish in the end) -- I made the mistake of first feeding NLS to the fish and it would take a while for them to eat it. They ate the bloodworms quickly and had no problem stuffing themselves with it. ...

Type of Disease: Fungal Disease
Disease Name: Saprolegnia
Additional Names: True Fungus, Water Mold

General Information:...

Type of Disease: Viral Disease
Disease Name: Lymphocystis
Additional Names: Cauliflower Disease ...

Type of Disease:Protozoan Disease
Disease Name:Malawi Bloat
Additional Names:Cryptobia iubilans

General Information:...

It has been my opinion for many years, that unless you catch it before any die, then Metro is fine to cure it. BUT...once you loose a fish, or fish go a couple days and no eating, there is nothing that works better than CLOUT. Use CLOUT in this method. Start with a 50% water change. Then dose as prescribed on the bottle. Then Second day dose as the bottle says Third day dose as the bottle says. 4th Day, 50% water change and dose per bottle... Always treat for 5 days if even all fish are eating. ...