"RubenD" wrote in message
. com...
I have 3 questions about mixing fish:

Is it due to the toxicity GF spread in the water?

All fish excrete waste into the water. That's why you need to keep doing
partial water changes.

How about if you take care of the water condition with weekly water
changes?

You still have the temperature differences. Tropical fish like warmer water
than goldfish.

Are humans suceptible to fish diseases in any way?

Yes, a few. Google the subject.

Thanks in advance for your comments,

Koi-Lo