most aggressive catfsish under 2 feet?

[thebiggerthebetter]

From observing my 5 walking catfish I've picked up from a drying pond:
1. At 4"-5" in a 55 gal, the two bigger ones were chasing the 3 smaller ones around the clock. The smallest was dead in a few days. The others learned to stay away, hide high up in plants and not go to the bottom. Another was killed in a few months.
2. In 1500 gal at ~8"-10" with hundreds of non-swallow-able pond mates, they were fine but after 1 year found only 2 at about 14".
3. In 4500 gal tank they did not bother anyone to any significant extent as there was plenty of space to move around. They liked to cozy up to each other, almost tenderly. Spent about 8 months there.
4. Back in 240 gal with ~10 suncats and a flowerhorn for 2 weeks - bugged the suncats to no end, nipped fins mercilessly, so went into another 240 gal with a 1.5' pleco and a 15" Labeo species.
5. The Labeo killed one in the second night together, and the other a day later http://www.planetcatfish.com/forum/viewtopic.php?f=9&t=41670

 

[thebiggerthebetter]

3. In 4500 gal tank they did not bother anyone to any significant extent as there was plenty of space to move around. They liked to cozy up to each other, almost tenderly. Spent about 8 months there.
4. Back in 240 gal with ~10 suncats and a flowerhorn for 2 weeks - bugged the suncats to no end, nipped fins mercilessly, so went into another 240 gal with a 1.5' pleco and a 15" Labeo species.

Forgot to mention that the 10 suncats and the two walking cats have been together in that 4500 gal the entire time and the walking cats didn't notice the suncats at all, whilst when moved to 240 gal, the suns have lost ~1/4 of their finnage within several days.

I observed the same with my adult flowerhorn. A well-behaved citizen in 4500 gal and a merciless bully in 240 gal.

Tank size has a very real, striking bearing on such fishes' behavior.

But even this rule, as all rules perhaps, has exceptions - such as the Labeo species per the thread I linked above. It is a nightmare in 240 gal and a bit less of a nightmare in a 4500 gal.