I used to fish Grassy Sprain when I was a kid. We're talking around '68 or thereabouts. At that time fishing was verboten, which you wouldn't have guessed by the numbers of people fishing there. I would fish the flooded trees near, I think it was Jackson Ave?, memory's not clear. This was before the parkway was extended. Caught fish.
Let's be honest, at 15 any fish was a good fish. But I did see some whoppers breaking the water now and then.
Things being what they are today, personally, I wouldn't risk tresspassing or anything so checking with the proper authorites would be a good thing.