I started fishing for trout when I was 7 years old and lived in Norway. So, that's 48 years of trout fishing experience and I just learned a new fact. All nets are not created equal. The type of net I have used for years - an inexpensive nylon knotted net - is harmful to trout. Since I fish for both bass and trout, the thought never crossed my mind that what is fine for one species - one that sports scales - is damaging to another that uses slime for protection. Geez.
As a dedicated C&R guy, this shook me up pretty good. I discovered this on my path to covert from spin fishing to fly fishing. Part of that journey is reading and research on fly gear - that's where this fact jumped out at me. It turns out that the nylon knots in your typical inexpensive net grind in and scrape the sensitive skin of a trout. On the other hand, the softer trout net allows you to better support and cradle the fish without damaging his protective coating.
Here's the good news. There are cheap trout nets out there. I had picked these up and looked at them in the past, but was put off by the $30+ price tag when compared to $5 for a nylon knot net. I was in Dicks Sporting Goods the other day and found one for around $12 - with the wood handle and everything.
Bottom line - if you fish for trout, and have the knotted net, switch to a trout net as you start the coming season