catch a wrasse in large sump ?
 

overflow screen moved and little bugger got from my tank to the sump.

Are there easy methods to catching return to the main tank?

Nighttime would be easiest IMHO.
If you can form a barricade to decrease his area even better.

not going to be able to do that .. it's a 220 sump and about 1/2 of it has live rock

Bad news, you probably won't be able to catch it....good news, the wrasse will thrive in a sump full of live rock and all of those pods.

What Adrienne said.

If the sump isn't covered, he'll find a way out himself.

I hope he doesn't jump out... :fish2:

Wrasses are jumpers.

If he were mine and it was just a rubble pile, I'd prepare a sufficient vessel with sump water, shut down the system, move all the live rock over there, and plant a cut-to-fit piece of plastic across the middle, then start squeezing the space until I had the rascal in one place or the other. It once took me an hour to catch an amazing red-stripe 2" goby in an 8" pump chamber, but I got him, undamaged. I'm stubborn that way.

What does he eat? Would a fish trap not work, maybe some frozen food in there?

Years ago, I had a similar issue w' a banana wrasse (but I was trying to remove it from my main tank for 'bad behavior'). It was very wily and evasive, burying in the sand if it felt threatened. So, I purchased the smallest fishing hook I could find, tying it to fishing line (which I attached to my 'fishing pole'- a pencil). I baited it with some shrimp meat, and it worked like a charm. I removed him (unharmed). Give it a try.