I use a DIY fish trap. I bought some acrylic from Home Depot and some glue from Hobby Lobby.
In this case I had a Lamarck angel that developed a taste for my Wellso. The poor coral was shrunk up to nothing, so I put it in the trap for bait.
The next day I had the fish caught and brought to my LFS.
The rubber bands help slam the door shut so the faster fish don't escape. Just be careful not to slam the door on the fish.
For algae eaters, I have a piece of gutter guard a little taller than the inside of the trap and the same width. I folded it in half with a heat gun.
I put algae in it and shove it in the back of the trap. Within a day every algae eater is going in and out of the trap. My starry blenny just lounges in the trap and pigs out.
Works like a charm, but it does take a day or so with it just in the tank so they get comfortable with it and will go in and eat.