I had no luck catching the red tailed black shark in that pond, either. I searched online and found a suggestion to try the small fishing area at the back of Oasis Spring's park (the one close to the cave entrance). I eventually caught it there. As for the bait, having the preferred bait may improve the chances of catching a certain fish, but in completing my collection, I caught most fish without any bait at all or with the wrong bait.