first off, for what they say is "unatural" we're the only species on the planet that irradicates our own enviorment, and to commit premeditated murder with the exception of gorilaz, our cousins in species. they say that murder is inhumane but humans are the only ones that do it.
second, to say that the captivity of fish and the action of 2 fish species in captivity to interbreed is unatural is untrue. i think we ignore the fact that we destroy this planet by ignoring the fact that we too are part of nature. mother earth created us and everything in it. if a human catches a fish and they breed thats natural. if an army ant captures a different colored ant and makes it breed with theirs, or work for them, its natural....not to say this is right, but its not any 1 individuals decision to make, and those who pass judgement, will get whats deserved.
you know its funny, if every1 on the planet died except 5 males or females, and aliens came down to breed with us to ensure the survival of atleast some of our species gene's who wouldn't do it? we're talking hot alien babes (just incase your like "de de deee what do they look like") so you may say that fish in a mans tank is unatural, interbreeding is unatural, us in gods, or whoevers universe is unatural, but what it boils down too is your wasting your time making false accusations and bashing something not worth wasting your time on, in return making me waste my time trying to get you to stop wasting your time ....etc etc etc. you see the pattern?
BTW cool fish i saw the spawn pics. i have a devil that would not breed with another devil, but a flowerhorn instead. so

HA! was his choice not mine in the first place he's just doing what he NATURALY has to do to ensure survival of his genes