I can see there mouths on the surface, this time of year they are sucking on the top, I guess their mouths are and inch at least. If i had a cast net, it would be nothing to get half a dozen at a time.
My neighbor said, some years ago, not sure how many, some mexicans use to come buy and net the pond, he ran them off, it is private property, not really funny at this point but they could have been helping the pond more than damaging?
