Guppy, those are instant tanks, set up overnight for Aquarama... an Aquarium trade show. There are no small fishes in those tanks at all.
The people we think set up those tanks have at least 2 planted asian arowana show tanks at their shops. Both arowana's are at least 1.5 ft long. One of the tanks has 3 inch or larger flying foxes and SAEs. The other has hundreds cardinal tetras. I've asked about the tetras... they do get eaten on occasion.
One guy I know keeps altums and cardinals in his arowana planted tank. The arowana leaves them alone in the day. When the tank and room lights are off, their reflective scales invites bites from the arowana.
This is mine.
She's in there with SAEs, otos, tiger barbs, khuli loaches, cigar fish and a handful of shrimps that survived.
She will try for any fish or shrimp that fits her mouth and that she thinks she can catch. Most times half-heartedly.
Shrimps are prime targets... she zeros in on them as soon as she spots them. With fishes, she tries for those that are not paying attention to her. She sometimes swim right by them without trying, but if she spots one being distracted by something or other, she'll make a beeline for them. Most times they are alert to her whereabouts and will keep a safe distance and behind her. When she's resting, they all come out to play and graze. When she starts cruising, some will hide and some will simply stay alert and keep safe distance.
Feeding time will see the tiger barbs making runs for the food (thawed market shrimp) which I drop piece by piece. They flee when she gets near. The SAEs used to do that. Then one was slow and got caught because it was between her mouth and the food. They don't anymore.
Key points:
- Keep faster agile fishes with predators.
- Never put in any fish you are not prepared to lose.
- Plant heavily.
- Keep the predator well fed. They are less likely to make a serious attempt on any fish for food reasons.
- Fishes that stay in different levels of water do well (example, arowanas are top/mid-water hunters, cories are mainly bottom dwellers).
- Small fishes are better able to duck into the plants for cover.
Depends on the temperament/taste of the predator too. I know someone whose arowana ignores the not-very-hard-to-catch feeder goldfish. In fact the 2 goldfish were it's tankmates for quite a number of years. OTOH, my arowana has a taste for SAEs and at least once went near vertical to try for an SAE on the gravel. The SAE nearly didn't get away.
I ramble...
