Nice concept but too soft to score well, with what looks like motion blur as well as overall being out of focus, and coloured fringing - presumably from refraction on the aquarium glass.
I love the lion fish. This meets the challenge well. I know you could do a much better job if the little lion would hold still but I'm sure he just keeps moving. The colors are just a bit muted for my taste but being reminded this is minimal overall you did quite well catching the little bugger as well as you did. I give this one a 6.