I learned my fish taxidermy from a guy who was a full-time fish only taxidermist, and who was advertizing to teach just a few people his fish methods.
It worked out great for me, as I worked mostly evening and nights, and was able to work right in his shop for 9 months. NO way was I going to work on his customers work, but he had extra fish for me to learn and work on.
I worked on many different species, including a 25 pound Chinook salmon. After my nine months, he said I was done.
After that he did hire me part-time, I did alot of fish skin cleaning, and made many stained wood panels for him. about 1/2 of this extra work I did in his shop, and I was still able to learn from him and watch him work.
He IS the best fish taxidermist I’ve ever seen.
that was over 30 years ago.
Good luck.
Jack.