I was just realizing those two ( predatory and really active) don’t exactly go hand in hand. I was just looking at other members tanks here and I really like Caveden s bichir tank and was wondering if I could do that on a smaller scale. 2-4 bichirs like delhezis, 1-3 hujeta gar, and perhaps a satanoperca daemon or a silver datnoid with some dithers. Would that be overstocked? I’d be doing 85-90% water changes weekly.What you want is near impossible. Most predators are of the ambush type. Meaning sits until lunch swims by then, then attacks.
Best I can suggest is a big group of Pimelodus pictus. They only get to around 6in. But in a group they move around a lot searching for food. Get around ten or so
Then some Andinoacara Pulcher, a smaller cichlid that resembles its cousin the Green Terror, Andinoacara Rivilatus. Can establish a breeding colony and the pictus will dispense of the fry. Get some larger bodied tetras like Buenos Aries or Columbians as dithers, get a big group around 15 to 20 or more to really get the schooling effect from them.
This tank should be nice and active. The cats always on patrol. Cichlids doing they thing and the tetras schooling about.