Not sure where as a debate over the best fish kibble helps OP's or anyone else's cause.
I'm not familiar with "Clout" - However it is definately something I will learn more about. Cupramine, I am somewhat familiar with, a few of our LFS's treat their systems with this because of the varing sizes and species of both freshwater and marine livestock. Prazzi's is too rough for many species to handle. I also liked his suggestion about using a BUCKET - keeps the cooper out of the tank. I've used cletted cooper for externals with great success, it's the only med I'll use for toothed Characiformes.
2 of Op's fish died, doudtful they died from internals as internals can take a very longtime until they are large enuff to even cause any real damage. It's possible that if OP used clout, prazzi, or cupramine in a Bucket - theses fish would still be alive.