Schooling fish question

[Argentis]

Hey folks, I've one big question.

If you have one species of schooling fish, and later add more of the same species to the same aquarium, should they school together?

Background:

Over a year ago we had our 29G set up with a small community of fish - we had some Cherry barbs and Neon tetras plus some Danios that were left over from another set up.

During that run, we lost more than half the school of Cherry Barbs - we're not sure what happened with them, no ick or any visible disease -- that's besides the point.

In our 75G that we upgraded to, our neons, danios and the remaining 2 cherry barbs were carried over -- and we added sword tail platties (males) & Sailfin Mollys (males). - it has been running this way since Boxing day -- We also added a school of cory cats, Bushynose pleco and then an opaline gourami joined in too

This past weekend we finally found Cherry Barbs in one of our LFS (they're not terribly common it seems in our area) - and picked up a school of 6. -- we also picked up a pair of Electric Blue Rams
(This tank is utter chaos for stocking)

Everyone is doing fine, no bickering or anything, but the Cherry Barbs don't seem to be schooling up - one swims with the danio's at the top of the tank, a few think they're neon tetras, and some of the others kinda loosely shoal, when they're not hanging out with the cory cats or swordtails...

The original barbs broke up after they went from 3 down to 2 - and only loosely shoaled on the rare occasion, but more than often were found on separate sides of the 75 by two different sections of planting & driftwood.
The 6 at the LFS were schooling well in the display tank when we picked them.


I just keep thinking now, Did I somehow break the fish? Or will they eventually sort themselves out and group up?

Going back to stocking: the Opaline Gourami wasn't my choice, Hubby picked her up and loves her dearly, but knows that she may turn into a right old cow when she gets bigger. The livebearing crew and maybe some of the danio's may be jettisoned from the 75 into the 29. We need to talk furhter

[Slaphppy7]

I have 10 or 12 (haven't counted lately) CB's in my 40 gallon tank, males and females, and they've never shoaled or schooled together.

[Argentis]

I have 10 or 12 (haven't counted lately) CB's in my 40 gallon tank, males and females, and they've never shoaled or schooled together.

That makes me feel a bit better, but annoyed that they're listed as a schooling fish and have decided not to.

[Rocksor]

shoaling behavior happens in the presence of predators or nervousness. The fact that the CB spread out is an indication that they feel safe, and want to get as far away as possible from other CB in order to reduce competition.