Personally I am against the use of nets for these fish at all. They often will get stuck, and will either cost the net, or the fish. This is a VERY stressful method, and is not recommended. I personally just reach in and direct them to a corner. Then (dependent on the size of the pleco) I will either use my other hand to come in from the front, or just move to the head. The goal is to get in front of the pleco in a place where they cannot turn around fast. Put light pressure on the head, and slide it up to the top of the tank. I then slide one finger under the body of the fish, and slowly slide toward the head. This will gently coax the fish to release his grip. Just like that, and the pleco is out, faster than with a net, and has been out of the water for a minimal amount of time.