This quote is from another thread. I quote it here to keep the original thread on topic:

Quote Originally Posted by JSFMACLJR View Post
The salmon buttons are worn by the Duke of Argyll AND and the Chief of the MacLeans, in the case of the photos by Sir Lachlan Maclean of Duart and Morvern. Salmon are totems of many Westerns Highland/Isles clans and are badges of both the Duke of Argyll and Maclean of Duart.

Now, they are hardly "restricted" in any legal sense of the word. "Good taste" though, is another matter. The shield of my coat of arms bears three salmon, but it just wouldn't be done for me to have buttons made up as salmon. If Lord Lyon saw fit to grant me a badge of a salmon naiant, then I might consider salmon buttons, but I still would be reluctant to wear them in certain places.
Since I am not familiar with such badges, I have a couple of questions;

1. Under what circumstances would Lord Lyon grant such a badge?

2. Where, if anywhere, is such a badge displayed in an heraldic achievement?

Thank you!