I have experimented with trout and suckers and found them to be a decent base for lures/bait in land trapping. I have never tried carp or salmon so can't comment there but if RdFx says they are good i'll take his professional word for it. Several years back a reknowned lure maker made a comment in his catalog that "A fish is a fish is a fish." I knew right away that the lure maker was rationalizing off the top of his head and had never actually tested that theory. Believe me, a fish is a fish is a fish is not so!!! There are specific fish species that will elicit very emphatic responses from canines and cats and other species that will be absolutely rejected. I had experimental dirt hole sets all over the country one Summer just to test the effectiveness of certain fish species. I had fox and coyote coming on a regular basis to fill up on one species while another hole filled with a different species afew feet away would be rejected by every passing animal. Some species were so bad that I couldn't even get domestic animals to touch them. I tried them on dogs, cats and ducks and they all couldn't wait to get away from them. On the other side of the coin I have seen these same animals and ducks gourge themselves on certain species until they could barely walk away. There were other species that were somewhere in between in response with many of them just being picked at by both wild and domestic animals. So, one must do some pre-season work to see for themselves if they want to use fish as an attractor for land animals. Even though all fish smell similar to us, animals can detect something about them that they like or dislike for some reason and react to them accordingly. Ace