At that size Sunil, BNM may have been in it at the time your pond was built... IME, BNM seem to not be found in real small creeks, but when they get to the 10 foot plus in size, they are in nearly every creek that size. If you aren't seeing schools of them along your pond's shoreline, they probably were never present though. With that kind of habitat, I'd say they'd be fairly easy to introduce though.
