[Baby_Baby]

First, do frequent water changes. "Velvet" isn't very infectious, and it
usually attacks weaker fish or those shocked by sudden tds change, etc.
Healthy fish may carry a few and never show symptoms or distress until
ammonia gets too high. Then "boom."

Nothos seem more capable of getting it than many other killies. For that
reason, most experienced breeders routinely add plain salt (non-free-flowing
type NaCl) to their water at about one tablespoon per 5 gallons. It inhibits
the reproductive cycle of the parasite. [Don't use "Ocean" salt as the mixes
for saltwater tanks are buffered to about pH=9.4! Use kosher, rock or table
salt.]

If the water is clean, fresh and well aereated, the simplest treatment is to
raise the temperature to 93-94F (33C) for 24-36 hours. Add some salt if you
like, but some catfish and Amazon species don't tolerate as much as
suggested above.

Quinine sulfate, quinine HCl and Copper sulfate are also effective but can
do in snails and plants (and other fish as you discovered). Use carefully
and *exactly* as directed. No guessing.

*Oodimium*, the flagellate that causes "velvet," is dropped off the fish in
cysts to rapidly divide in the substrate. Hundreds of new ones hatch in a
day or two. They must find a host within 24 hours or die, so velvet can't be
carried for long in any tank without any fish hosts.