Can i use the green magnet light to attract catfish?

If so how should i set everything up. I used it in indian creek the other night to try to cat some spottycat but all it attracted were thousands of tiny shad and a gar fish. We sat for hours waiting. Do i maybe need to sink it to the very bottom? Do i use it in deeper water? Maybe very shallow water? Any help would be very nice. one last thing, would it work in a flowing body of water such as a bayou or river?