Maybe the Salamander is refusing the nightcrawlers because they are cut up and not moving around as much? When I was at Riverfront at night I always got to watch them feed. They just dropped in a massive amount of nightcrawlers and all the Tigers were just going nuts like a free-for-all. They werent used to them being cut in chunks and every Salamander there had a worm in its mouth. Id just try full worms and not worry about cutting them up.