"Little is known about the breeding habits of the Bala Shark, though they are an egg scatterer. They have been reported to have bred in the aquarium, but are not yet bred commercially." http://animal-world.com/encyclo/fresh/cyprinids/balashark.php
balas require a large pond of atleast 12'/4'/3'
i heard of bala sharks being bred in INDIA in a place called CHENNAI,
have never seen them personally but have heard about it,
though i had seen a few large bala sharks in very large ponds and of a very large size ,around 14-16"