I have a 2 cup measuring cup I use to do his partial water changes, and to get him out of the bowl. It's big enough that if I dunk the cup in fast enough, and if he's close enough, he gets sucked in before he could try to get the strength to swim out.
If he's being mopey though but still near the surface, sometimes I'll dunk the cup in the water and hold on to it for a minute or two, as everything stills. Eventually he gets curious enough and swims towards the edge of the cup. If he inches a bit inward, SCOOP! He's mine!!! ... Well, he's already mine, but you get the point <3.
Sometimes I do the same with a net too, if he's being sad on the bottom and I can't get him with the cup. Usually he flees as soon as I stick the net in the water (like he knows what's coming <.<) so I have a really hard time using the net. I found if I leave it still in there for a bit, or move it realllllllllly slowly towards him, before I go in for the catch, that tends to work too. Kinda depends on your fish and his mood =P.