Okay. Now we are solving this puzzle. I didn't want to be the bad cop and bring up all the "holes" in his statement. The fish with whiskers was either a member of the catfish family or a common carp. Absolutely NO whiskers on a grass carp!. If the fish had scales it was most likely a common carp; aka bugle mouth, or sewer bass. You will get many, many opinions here how it got in there. Anyway, it is there, and it probablay has brothers and sisters with it. As the population increases in numbers your pond will become more and more muddy looking.

LM bass and larger channel cats will feed on the young carp. Keep your numbers up for the bass and catfish. You might want to have some carp fishing derbies for your fishing friends. A prize for largest and most carp caught. You may have to annually restock 10"-12" catfish until larger cats start showing up in the angler's catch. Restocking catfish 8" or smaller will mostly be expensive bass food. It would be cheaper to feed your bass beef or pork steak or ham than 4"-8" catfish!

aka Pond Doctor & Dr. Perca Read Pond Boss Magazine -
America's Journal of Pond Management