I bought a file fish to take care of majano's and it did a great job until they were gone. then he started pecking at my Acans! so I put my home made fish trap in the tank with an Acan inside, 3hrs later during my saturday afternoon nap, my daughter says Dad arent you trying to catch that fish? he is now in my sump!
here is a picture of the trap with my pygmy angel in it when I was trying to catch a crab.
I don't suppose you have a "plan" or design for this.... I have one damsel I still would like to get out of my tank!!!!
it's real easy to make, you can decide how big you want it. this one is about a 3x4x6 inch accrylic box glued together except the the top. I have rubber bands holding the top on. there is a small gap on one end just for water to go through and a ramp on the other end that the animal can easily go into but has a hard time trying to figure out how to get out. kind of like a minnow trap.