Hi all,
I'm looking at a bottle of metronidazole (Flagyl) right now. It would be used to kill amoeba and protozoa. It also kills gram positive and some gram negative bacteria.

The treatment protocol is different for fish and for reptiles, but the bottle says to treat fish, add one tablet for each 10 gallons (38L) of water and to retreat in 24 hours. The fish (or tadpole in this case) should remain in the solution for 5 to 10 days.

If I were going to feed the fish or tadpoles to a snake, I would change their water after their treatment and give them at least a week in fresh water to pass the medication. Otherwise, you'd be treating your snake with Flagyl, which is safe, but you wouldn't want to expose any organism to low doses of medication for an extended period.

As far as collecting eggs, I don't think it would be a foolproof method, but the chances of the eggs being parasitized would be a lot less. I suppose it depends upon how heavily parasitized the water was, where the eggs came from.

The tail of a tadpole is like the yolk sac of a bird or snake... it's provided to stimulate rapid growth and is a complete nutrient source.