Thank you to all for welcoming me.
I am from Trivandrum so can give some idea
About fishing locations in TVM. the beaches around Vizingam fishing village-- (Trivandrum), Kovalam beach and Varkala beach are all good. Careful of the high waves though. Can catch a lot of squids at Vizingam pier. During the winter months we can see the rocks full of mussels, they are very attractive to see. if you fancy eating , its very cheap during season, also could be good bait.
You could try Velayani lake for freshwater fishing, did not fish there yet (lots of terrapins)...but have gone just to relax and enjoy the scenery.
The river fishing is also good, lots of walla (catfish). Near Neyyar Dam the river is good for common Carps (locally called paral), Catfish and Thilapia-
but need to ask permission from the prison officer there prior, they are all friendly and cooperative, including the life inmates , whom you see working on the gardens.
The Dam premises is close to the Kerala Open Prison System,
There are local rumors of the river waters infested with crocs- used to fish there but never seen any, in any case would just finish up before dark. But there is a crocodile farm there, which is a good place to visit , if you admire crocs. All the crocs have their own names, some named after movie stars- Prem Nazir, Jayan etc.
There are lots and lots of local ponds in and around Trivandrum City. but now a days the, these ponds are maintained by their respective rotary clubs etc, as they are raising and protecting the local Fish population , and they only tolerate the nearby residents fishing there. So I just go to my local pond and fish for carp, and release them.
Other places I have fished is Kumarakom lake near Kottayam District is a good place for carp and murrel (locally called Varal ,Bral), sunspot (Kareemeen).
Hope my amateur tour guide suggestions are useful.