I have a 29 gal Fowlr with 20lb live rock and 40+ lbs of crushed coral and live aragonite substrate. the tank was set up and ran with ls/lr for 3 weeks. after nitrites and nitrates settled to 0 I added two tank raised clowns which had been together. the LFS owner said they were about 6 mo old.

both fish were eating swimming and seemed to be settling in. they were being fed a diet of frozen foods including: marine cuisine, squid, seaweed/vege mix and occasional brine shrimp. they are fed in the morning and at night.

the lights are now on a timer but were not at the begining

On day 7 of being in the tank I went out of town early in the morning for a funeral. i forgot to feed them, and to turn on the light. the only light they had was the little bit of ambient light that shows in my living room during the day. I came home that night to find the larger of the two fish floating nearly sideways in the tank. fin movement and resperation apeared to be normal. but she/he was having difficulty swimming upright and swimming lower into the water column. I turned the lights on for a few hours and fed them. both fish ate normally. After being in the light and eating she resumed normal swimming patterns.

The next morning she was again near the top looking sluggish and swimming sideways. Again she ate and began swimming normally after the lights were on for a while. This pattern has continued for 4 days with her being near the top in the morning when the lights come on and then resuming "normal" swimming patterns after the lights are on for about an hour. I have increased the photo period from 12 to 13 hours since this is when she seems to do well.

testing results:
steady since tank was started
specific gravity 1.022
pH 8.0
temp 76
steady since fish were added
ammonia 0
nitrite 0
nitrate 0

Does anyone have anything that can help me? What is going on with this fish?

I have had countless clown fish but always had an assortment of anemones for them to host. As long as they are eating and seem to snap out of their trans, I wouldn’t worry too much about it. In about 6 moths, you should consider getting a BTA for them to sleep in. Clowns will also host some coral.

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Just a stab in the dark here but since this only seems to happen when the lights are off and it becomes alive shall we say when the lights are on, the fish may very well be sleeping so to speak.

I had 2 Clownfish and when the lights went out 1 went behind the Pipe of my Cannister Filter and the other went behind the pipe of the other side off the tank, when the lights went on they started their normal swimming about the tank with each other.