The most I've kept at once is 5 (not practical to keep more than that in a 55 gal) - They all exhibit the same behavior (regardless of school size) in my (limited) experience...5
mine is totally insane, my GT just looks at him confused all day. he doesnt go near the bottom of the tank, just swims and swims and swims full speed back and forth and up and down
Heads up, "-I learned that if you experience your pictus catfish consistently (daily, regardless of water changes) swimming up and down the tank, it is uncomfortable with the water parameters (PH hardness, etc...), and is incapable of adjusting".
I doubt they'll thrive and live as long as they can if the parameters were met. However, we all know how info is on the web and from certain LFS' so take it with a grain of salt, or a LB
My spotted pims were great together and my four-line are great together now..
I'm thinking the attitude of Pictus cats can vary in each individual fish
My pictus won't go anywhere without each other. I had 3 of them until the father of my breeding krib pair killed one. I moved the two survivors to another tank and they just sat in one place for two days which is very uncharacteristic of them. Recently I purchased a few zebra loaches and one of them thinks it's a catfish and pal's around with the pictus all day. Seems like they've replaced the lost pictus with a loach and they are happy again.