Hawaii 4 line wrasse ate my cleaner shrimp

[Frogger]

I have trained my fish to come into a net to receive food. I have a large Collaspsible fish trap. When I added my last 2 fish I tricked my most aggressive fish (yellow tang) to come into the net scooped him up put him in the fish trap/acclimation tank. Put the new fish (Kole Tang and a Melanarus wrasse) into the tank. After about 10 days let the yellow tang go. A little bit of tail wagging between tangs but the Kole tang had its own territory and wasn't abused. I could have also put food into the trap.

I have also in the past had a couple large pieces of egg crate that I used to divide the tank into 2/3rds and 1/3rd. Does not work any more because my corals have grown into the gap.

Never tried the mirror thing only saw a video.