Quinine sulfate powder residue

[Deinonych]

Good idea. I'd guess, that because CP is a med that requires a Rx from a vet, marketing would be impossible.
;

True. However, metronidazole is also a prescription med for treating protozoan diseases in cats and dogs, yet we can buy it "over the counter" from NFP. I think the financial hurdle of getting a new medication approved for ornamental fish is the more likely barrier.