My rtc fins tales rooting

[Fishman Dave]

I find young rtc will be happy for a decent cave (half a clay flowerpot) or rock to use as shelter/ hideout. Would expect him to learn quickly if it is happening at night when he will be in his element out of the two of them.
In my view silvers go by eyesight and I don’t see him attacking at night unless just by chance and not targeted. But by day will be different and could go for the redtail if he feels the redtail is after his food or a threat.

 

[fishdance]

Need to use a dim night light (often called a moon light). I use a 5W LED left on 24 hours. This let's any smaller fish better escape getting eaten by the aro and more importantly reduces the aro getting suddenly startled (and smashing itself up) by sudden noise or movement.

Use two caves for the RTC as it will feel better having a choice. Make sure the cave is long enough to provide protection to reduce stress. I prefer a long pipe that has 2 open ends but a low blind cave that let's the fish turn around will do. The RTC will quickly outgrow a small cave but a cave that's too big will not feel secure.

Yes, RTC has a very good chance of eating the aro when it gets bigger. It will "fold" an aro longer than itself so it can swallow it.

If your tank is big enough, you can keep both species together but expect some casualties along the way.