Can fish stock be left simmering for a long time without damaging the flavor?
I am a European trained chef. This is a very interesting question and there are quite a few answers. In my opinion and experience, the simmer time of a good fish stock is 100% based on the type of fish bones that you are developing the stock with. I remember asking the question many times on my travels through Europe and North Africa. I will share my preferred methods for a few species of fish.


Turbot, 20 minutes after it comes to the boil, bay leaf only in the stock.
Dover Sole, a full mirapoix, simmer for 30 minutes.
Salmon, bring to boil and shut off, a full mirapoix is needed
Northern Hake, 45 minutes full mirapoix
John Dory, 45 minutes full mirapoix, white wine may be added if desired.


I hope that helps you out. Regards.

Michael