I have three bala sharks in my 100G tank, and two in my 55G. When feeding the two in the 55G with other community fish, I saw them acting weird. They are rather small and immature, so I don't think that they were mating, but I don't know. I do not and have never tried to breed any fish. I have no experience with fry and immature fish. It appeared as if they were swimming extremely close and rubbing against each other, while staying upright. I think that they are too young to breed, but I have no experience. Are they breeding, or something else?

i've got 2 bala's that do exactly the same thing.....would be interested to hear peoples thoughts. I've had mine for 3 months.

Balas are big fish, 400mm and up, and probably don't spawn until nearing adult size. What you may be seeing is a "test of strength". Dominance behaviours are very common in Cyprinids, and equally varied, some fish relentlessly chase, others flare their fins, the "spiral dance" is well known to many barb keepers. Lining up and shoving each other - don't know, but could be.