how old was the brook trout ?
Believe it or not only 2 years old at around 18 inches. I had some 2 years olds as big as 19 1/4. I had some parasite and bacterial issues in the pond that fall and treated the pond with a minimum amount of potassium permanganate and ended up killing most of them. (At least I was able to scoop them up and sell them to other taxidermists).
I thought it was necessary because I was losing two or three a week. Turns out I probably should have just left them alone and just planted more initially to compensate for losses. Brook trout are very touchy compared to browns and rainbows.
If I would have kept them for one more year they would have been in the 22 - 24 inch range and 5 to 6 lbs. Just like the government I do more damage by doing something.
If I raise trout again it will probably be in a barn in large recirculating tanks where I can keep parasites and pathogens out and control the water quality and temperature better.