will different tetras school together?

If you add two different kinds of tetras, lets say 6 neons and 6 rummynose, will the 12 school together?

I don't think those particular species would school together, especially as the rummies are considerably larger and faster moving than neons. Sometimes very closely related or similar looking tetras will school together, though.

I have a 30 gallon tetra tank, with black neons, neons, and von rios. They do not school together, but rather form 3 distinct groups.

I doubt they would as well; I don't have Neon's in the tank; but I can tell you my Rummy's only stick together amongst themselves and no one else.

I have a 55 gal. community tank. I have 2 angelfish, 2 boesmani rainbows, 2 bushy nosed plecos, 3 bubblebee platies, 6 harlenquen rasboras, 6 espe's rasboras, and a small group of assassin snails.
I was surprised that when I added the 6 espe's rasboras to the tank that they would school with the much bigger harlenquen rasboras since they were so much smaller in size. At first I thought that they would be eaten by the bigger fish but they are all doing fine and since I added them they are getting bigger. I'm not sure it they are the same family as the Harlequen Rasboras since they are a dwarf rasboras. They are so cute schooling with the bigger Harlenquen Rasboras.

I imagine they were hanging with the bigger fish as protection from the angels.

It wouldn't surprise me that those two rasbora that eileen mentions, Trigonostigma espei and T. heteromorpha, shoal together, since they are very closely related species in the same genus, which was erected in 1999 by Kottelat when he moved these and the very similar T. hengeli out of the genus Rasbora. In my experience more with characins, I have observed exactly what iamntbatman mentioned, that different species of a genus will frequently shoal with each other, in small groups within the larger groups. For example, I have Nematobrycon palmeri and N. lacortei together and they are always mixed in groups of 2, 3 or 4 fish (out of 5 and 10 respectively). Similarly, my Hyphessobrycon bentosi rosaceus and H. robertsi do the same, and occassionally a male H. megalopteris [Black Phantom] will join one or two females of the others and display. But in the same tank, the cardinals [Paracheirodon axelrodi] and rummy nose [Hemigrammus bleheri] do not mix in with the Hyphessobrycon nor with each other, and vice versa.

It would be interesting to see if the two distinct genera of rummynose, H. bleheri and Petitella georgiae, would shoal together. The third rummy, H. rhodostomus, is in the same genus as H. bleheri so presumably might. I've not managed to find the Petitella; being somewhat "washed out" in the red compared to H. bleheri it is not as popular.

Byron.

Tetras generally do not school with one another. I have sepaes, neons, and rummys. All three form seperate distinct groups. I've heard some people report that neons and cardinals will school together but I have my doubts. In general if you want bigger schools of fish pick one breed and buy a lot of it

My observations thus far are that species tend to stick with like species.I am currently keeping Red Serpae,Lemon tetras,Von Rio tetras,Bleeding heart tetras, and Glowlight tetras. All seem to prefer to stay to themselves except for feeding time.
Have also observed that they frequent different areas of the aquarium. Some towards the surface,some favor the middle ,and some the lower region.

Yes, that's another characteristic. Characins do have preferences for the level they generally remain at in an aquarium. Cardinals tend to remain in the lower half, among plants. Hemigrammus pulcher tend to remain in the upper half. My Hyphessobrycon species tend to remain in the lower half. And so forth. Once one discovers these preferences, it is possible to have a community of fish that will fill out most of the aquarium, as opposed to the fish all being in the lower half or something.

Byron.