That's definitely not enough light to keep a nem. Plus, unless you've got the proper set-up & know what you're doing, IMO the pitfalls of keeping nems outweigh the cool factor of having one.
-First, there is no guarantee that your clown will take to it..... it could just as easily take to your powerhead instead, and clowns certainly don't need them to live out a very happy life.
-Migrating nems can be a hazard to just about everything else in your tank..... corals, inverts, other fish.......
-Many new nem keepers can have them for months & think they are perfectly healthy, when in fact they are dying from the inside out and don't realize it, only to wake up one morning with a nuked tank when it finally gives up the ghost.