Difference volitan and zebra lionfish

[Fish-guy]

I'm looking into buying a dwarf zebra lionfish. How can I see the difference in the store between a volitan lionfish and a zebra? Its hard to see when they are small.
I prefer them over a volitan lionfish because I don't want the big fish to knock over my rocks lol

Ps: I hope I put this in the right category

 

[Tony Gill]

The two species are in different genera (Pterois volitans and Dendrochirus zebra), so there is no shortage of differences between the two. However, many of the characters are difficult to see, particularly on small individuals. Perhaps the easiest thing to look for is the pectoral fins. In the volitans lionfish the pectoral fins are deeply divided, so that only the bases of the fin rays are connected with fin membranes. In the zebra the pectoral fins are broadly connected with fin membranes, leaving only the very tips of the rays "free".