The double surgeons is one of the strongest fishing knots. The clinch is a weak knot but good for beginners because it's easy.
With fine tippets I prefer the palomar and with the same day, same fly, same tippet I broke fish on a clinch that I landed with the palomar.
With larger tippets, like 10#-20# (saltwater etc) a blood knot is a good choice to join to leader because it is straight in-line.
At the fly, and with larger tippets the non-slip loop is a great choice as well but is not as strong or durable as a palomar because it uses only one strand thru the eye for one thing where the palomar uses two.
The only loop I like to use is the one joining the butt to the fly line but we all have preferences.
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