Having same problem with damsel. I almost caught with gravel cleaner end ( the wide part that cleans gravel removed from tubing) but it was too smart and I gave up. Trying to find link on how to do it
But here?s the secret?..put a hole in the middle of the bottle and, using your turkey baster, squire some taste treat into that hole. Leave the turkey baster in the hole and every once in a while squirt water into the bottle. This will create a ?snow globe? effect with the food, and make it more easily seen by the fish. Usually I can catch a fish within three to five minutes using this method.
I like Calfo's suggestion to simply drain the tank: with a large syphon and a good pump your corals will be out of the water for only a little while which will be no problem at all. This is perhap the least stressful way to do it if the normal scooping or trapping isn't working. Be careful to see where it sand dives so you know where to go and don't hurt it getting it out of the tank.
its very simple take a bag like the ones one get fish in thread a needle with dental floss or fishing line and weave it through the top like a sack tie a knot and put the other eng through so it will close when you pull the line. shut off the power head so it doesn't puss it around and place in a small rock to weigh it down shoot some food in there and he will swim right in you might even catch 1 or 2others too I did lol