.......short fin standard goldfish. much much faster than the fancy tail variety that you have and he was beaten the **** out of ....... some people may have gotten it to work but thats just complete luck.
recently, introduced a new oscar into my cichlid tank, not too small. ........ and seemed to fit in great, i watched himcarefully for about an hour until I was satisfyed he was safe. ....... went back ....... and there was the oscar in the top corner with his left eye completely missing getting his scales ripped off ........ and this is two similarly aggressive cichlids we are talking about.
Seems like your illustration shows that "it's just complete luck" whether things work out ANYWAY, bcuz even when following a better protocol with the O's tank mates, it sadly failed.
Basically, it's a gamble when combining fish or any animals.
If it FAILs for smokeythebair/mike, he may feel awful, eat crow, and get splattered by his wife.
It's his fish, his family situation and his decision, ideal or not..
I have no real opinion either way, bcuz he is not a beginner and says he has time to watch the tank.
How many ppl post about losing fish in awful ways, despite all best efforts?