melafix:tea-tree oil

Well, if they are the same thing, as you're suggesting, there's no reason why not. Although I think that the concs. of tea tree oil are probably higher than 1%, so it may require a little dilution before following the Melafix instructions.

What happy said. The concentration is likely to be MUCH smaller...it owuld be hard to dose unless you knew the concentration of the tea tree oil (make sure it really is Melucula oil, though, and i know I spelled that wrong).

Well, if the concs. higher and you know the concentration, it's easy to adjust, well ballpark.

use:
Conc. (init.)*V(init.) = C (desired)* V(final)

for example
if tea-tree oil is 10%, you could take 1mL of the extract, to make a 1% solution:

(10%)*(1mL)/(1%)=10mL final volume. So you'd need to add 9mL of solvent.

I don't know if tea-tree oil is water soluble, the name indicates otherwise (oil). I imagine vinegar would work. My first choice would be ethanol, but what about the drunk fish?

Right. Im just saying that I've seen bottles of it that simply say "tea tree oil" and don't give a concentration. In which case it would be difficult

happychem's hedge on emulsifiers/suspention agents is not to be ignored. You may have two liquids which don't readily mix.

Often naturopathic products don't indicate concentrations. This is one of the things that really bugs me about them. But that's a completely different gripe...

RTR, I supose Missy could always throw in a little egg yolk?

I am not saying that it is but wouldn't the chances of the Tea Trea Oil being solvent in water be good? After all you are adding the Melafix to your tank water. If it was not solvent how would it be able to help your fish.

You would have to know the "inert" ingredients in Melafix to know that.