Yup, first pic is definitely a golden shiner.
The second is a common carp for sure if that is in fact a barbel, which is looks to be. The most likely way the carp ended up in your pond was through stock contamination. Carp may have been mixed in with your GSH, BG, or others. If your ponds is fished with live bait, and some one emptied their bait bucket into your pond at the end of a day of fishing, that is another likely way. Last, small carp can travel long distances from one BOW to another in high water events... Just hope it was one fluke carp who road in with a stocking and he's the lone one. However, if he's 12" and your pond was stocked 4 years ago, that is unlikely and you most likely have a reproducing population of common carp. Consider setting some traps baited with bread to see what you catch... If you end up with a bunch of GSH, things are most likely not too bad. But if you end up with a pile of 2-6" common carp, you may need to do some serious work. Common minnow traps with 1" openings will only allow very small carp in. I like using bigger traps with larger openings. However, these can be hard to find as they are usually illegal to use in public water where most people do their trapping.
