Thanks I figured they would be sensitive to copper . Any recommendations on treating for internal ?While lions and eels can be tricky, starting with a small snowflake and training him in an observation tank, there should be no problem. Large mature snowflakes direct from the ocean, may be another story. Keeping them on a strict feeding schedule a snowflake would usually not go after fish, other than something small that they couldn't pass up. To wrestle down a fuzzy would be rare,
As far qt goes, copper is a nono, even if they survive treatment, they rarely live much more than a year afterwards, usually much less. Eels are very resistant to protazoan diseases like ick and velvet, so there really is no need for copper. Them transferring such diseases to your dt is also very unlikely. Now treating for internal parasites is highly recommended.
I keep all my feeder fish in a qt and try to feed them top food with selcon mixed in right before I feed them to my fuzzy