I think, based on many factors, including the size of your aquarium/pond, you may have to do a little more teetering as a rtc will need just a little more room than a bunch of oscars
How big is the aquarium that you are about to house these possible fish in?
Also, I think you have two similar threads open.
Snakeheads depending on the species are reasonable for an average aquarium. I personally like Chenna bleheri as it's extremely colourful like tropical fish even though they aren't. As for RTC you will need a giant custom made tank or a pond to keep one. Multiple Oscars 75 for the first alone and I don't exactly know how much after I'd assume a 125G for two?