Well I have two comments, and both are a bit negative. First it seemed that the knife was among the most dull ones I have seen. It did not look like cutting, rather crushing apart.
Second I do a lot of fileting every automn as I have the opportunity to fish with nets in a overcrowded lake. We try to reduce the stock of "tableknifes" or "thousandbrothers" by fishing as much of the small fish as possible. So I stand there with two buckets (20 kg+-) of trout/char and I fillet most of this. But this method is hopeless for my purpose.
The smallest (8in) end up as dog-food. Too small to bother with. Those around 10in are nice for frying, 4-6 is a usual dinner for two. I just cut the head behind the collar bones and remove the belly fins and the tail. When fried I split them along the back and remove the back-finn and the gut-finn and the main bone and there is two fillets without bones!
My wife also has a nice recipe for fishcakes using trout/char so I usually make some kilos of bonefree and skinfree fillets for this. Rule number one: razor sharp knife.
But I agree that the trout was a nice fat one, must have tasted great.