I would grow out any fish to around 2' then buy a rtc and grow it out to go in with them. If you have a tsn by the time the rtc hits 2' they should be around 30" and still rtc safe. Later on down the road the rtc will still out grow them even with a 1-2 year head start. Eventually you'll end up with a 36-40" rtc and a 30-36" tsn. I'll be keeping a channel catfish, rtc, rtc x tsn, rtc x marble, tsn, piraiba, rita rita, irridescent shark, and a jau together eventually. So that you know, when my last jau was still alive my rtc got his but kicked by it on a regular basis. Unless you have a massive, massive tank it's hard to get the kind of tank mates you will need with a rtc. My rtc was 1.5" almost 8 months ago, and is now 17". My rtc x tsn hybrid was 22" 2.5 years ago, and is now 37". Good luck with your cats. All the catfish I am housing with my rtc have a potential of 48" or more as adults other wise I would not consider it. My tsn had a year head start and the rtc has almost caught up within 8 months. My tsn is 20", and 1.5 years old, and luckily the other tsn in there with him grows even faster than he does. It is younger than my rtc and is outgrowing him. My rtc was 8" when I got my tsn at 3", and now the tsn is 19", and the rtc is 17".
