How long has your tank been set up? They generally need mature tanks.
I don't know if it is the lights, I kept an anemone under regular flourescent lights in a small/shallow tank for 6 months (i went away and the tank crashed...so I lost it), but PCs only 4" from the anemone should be fine. Keep in mind it would be much better off with more light, and I wouldn't try this with any other species.
37g mixed reef (primarily LPS). orchid dottyback (Pseudochromis fridmani), sixline wrasse (Pseudocheilinus hexataenia), 2 cinnamon clowns (Amphiprion melanopus), orange diamond goby (Valencienna puellaris), bi-color blenny (Ecsenius bicolor), and longnose hawkfish (Oxycirrhites typus )
10g planted 3 neon tetras (Paracheirodon innesi), juvi Apisto Agassizi