My friend Pedro had a pond in his grandfather's ranch, I estimate it may have been about 100 m in length and 50 m wide, half a hectare in surface, for years we fished that pond and caught nothing but dinks by the truckload, 8 - 12 inch fish all day long, I'm not going to deny it, it was fun because they were always very cooperative. One day we went to fish expecting nothing more but a good time but that day was different, that day I caught my first 10 lber ever, not only that I caught another one later in tha day and lost another biggie right at the bank .... the pond we fished for more than a decade and produced nothing but dinks.
So to answer to your question, yes, there is the chance that there might be something bigger and like in my case, it may take years before you catch it but you won't know if you are not there fishing, who knows ? maybe you will be there, that particular day.