Lionfish has fins and scales so is Lionfish considered a kosher species of fish.
Lionfish have fins and cycloid scales which (I believe) makes them kosher. Their scales are very easy to remove without damaging the skin http://oceanservice.noaa.gov/facts/lionfish-facts.html https://www.youtube.com/watch?v=8LiF2lkc60k
Also, Lionfish are much easier to prepare than most people believe. Removing the venomous spines can be done with a simple pair of kitchen shears. They can be filleted without removing the spines, but if you would prefer to do so, you simply need to cut off the dorsal spines, anal spines and pelvic spines.
Lucky for us, because they are delicious and nutritious!