Welcome aboard Jacko!
I don't think freshwater fishing in Chennai is even an option.
I don't know about anyone that does guided fishing these days, but there might be some chartered trips if you're will to fish from a boat.
If you want to fish from the shore like most of us here, then there are some places in North Chennai that are productive for Barracudas.
For GTs, Barracudas and Ladyfish (the ladyfish we have here can reach over 10 pounds) you can fish Kovalam beach that is about an hour and a half south of Chennai.
What kind of fishing are you planning to do, as in shore or from a boat. The tide seems a bit off that weekend for shore fishing, but it isn't too bad either.