Are we talking quarterly, half yearly or annually?
I guess you are talking about the returns. It is yearly. Normally the fry is released just after the rains and kept for 11 months. Being fed on everything form roadkill (Dam mangur) to rice and wheat husk to what the buffaloes do in the water the fish grow to about 1 kg plus.
On a good year the earnings (pure profit after taking out what they spend on cleaning, guards, etc) could be more.
The best part of the deal is that it is really a throw the fry in, once a month check on them, and do what you normally do otherwise.