Take the snap swivel off. Tie directly to the line. If there's a split shot on the line, move it to directly under the bobber, away from the hook.
There are less fish in your pond than in the local lakes. If your pond gets fished on a regular basis, and the fish and released back into the pond, they learn what NOT to bite on. The more natural the presentation, the easier it is to get them to bite.
Case in point. I caught a lot of BG on nests using a white 1" curly tail grub. They hit it as soon as it came close. I moved them to the pond. Could I catch them on the same lure? Heck NO! But, switch from a pink jig head/white body to a black jig head/brown body and they hit it.