Hello! I was originally going to post this in the ASAP forum, but after about 15 minutes in normal lighting, the issue seems to have subsided. I would still appreciate any insights anyone can offer as to what was happening here. New to the hobby, so my apologies if this is the 3reef equivalent of calling 911 for a hangnail... Brief description of the problem: I bought 2 new clownfish from my fairly reputable (from what I can tell) LFS yesterday. They were very active both in store and when I brought them home...never leaving the front of the tank. This morning I turned on my moonlights (I'm trying pitch black at night with a moonlight transition at dusk/dawn) I noticed them both staying near the surface, with one of them mostly on his side...looked like he was dying. The other was staying near, occasionally nipping (?) at him. As soon as I went to full light in the tank, the problem mostly subsided, but the one is still not straying very far from the top of the tank. My only theory aside from disease is that this is some kind of territorial issue? See video for an illustration. PARAMETERS (important) Temperature: 80.7 PH: 8.2 Ammonia: 0-0.25 Nitrite: 0 Nitrate: 5-10 Salinity: 1.023 dKH/KH/Alkalinity: unknown Magnesium: unknown Calcium: unknown Phosphate: 0 Test kits you own: pH, Ammonia, Nitrite, Nitrate, Phosphate Liquid or Strips: liquid Brand Name: API Are they Expired?: No Tank size? 60 gal cube Estimated total system? 70 gal Reef, fish only or, freshwater? fish only Current inhabitants? What and how many? 3 banggai cardinals, 2 clownfish, 1 lawnmower blenny Clean up crew? none How long has your tank been set-up? 2 weeks ( i realize this may be a heavy bioload for a young tank but so far my params are holding - if my test kits can be believed) Substrate. sand Type? aragonite oolite Depth? 2 in Live rock? yes How much? 50 lbs Did you recently add some? not since setting up system Filtration. Type? sump with filter socks & refugium and UV sterilizer Protein skimmer? yes Do you wet or dry skim? wet so far, not producing much yet Maintenance schedule for filtration? change socks 2x a week Drilled tank/hang on back overflow? drilled Sump/refugium. What's in it and how much? Refugium: 6 in dsb, 2 lbs rock and topped off with chaeto Macro? What kind? see above Lighting. Lighting type? LED Age of bulbs? less than 1 month Feeding What? dry spirulina/brine shrimp, frozen mysis How much? 1 cube of each How often? 2x daily Water change schedule. How much? 5 gal How often? 1x weekly What salt brand? red sea Water source? tap with RO/DI filter Additives/supplements used? none Do you have a ground probe? no What kind of flow does your tank have? moderate Thank you!