First off, congratulations on catching some trout!!!!!! Way to go.

As to your question about why they would only take a nymph once and not again,

The best answer I can give you is, “That’s Fishing”.

Usually that does not happen and no, the trout don’t send off messages to keep other trout away. Most likely they were not really in a feeding mood but were curious. You dropped in a new tidbit for them to check out and one would grab it. Normally you would just keep using the same fly and not have any problems. But, I have seen that happen before where one takes it and the others ignore it.

As for why this happened, Jim M had a possible reason, a different approach or possibly the fly was sitting in the water differently after the first fish. There are a lot of variables. Usually, if the fish are in a feeding state, they will keep taking the same fly, totally destroying the fly regarding how it looked when it first hit the water. By the time you finish fishing with it, some of the flies can look rather ragged, but still catch fish.

Chalk it up as a learning experience but one that you won’t see very often.

Again, congratulations on catching some fish. Bet that 18 incher fought good and hard.

Larry

Once it had been bitten they could tell it was a trap. next time try a popper bug.

different approach maybe