I've had my ocellaris for about 5 weeks now, and he's always had his favourite place in the back left hand corner, where he spends much of the day, including sleeping. But, before (up until 2 days ago) he's always bobbed up and down in the same spot there, until he decides to have a swim around.
But over the past day or two, he's been in the same spot, but spending much of it "sitting" on the bottom - almost motionless, about every 3 secs flapping his fins (as normal), then perhaps "getting up" and bobbing up and down for a bit, then returning, then going for a good swim, then back to his corner, etc. A good proportion of his time is spent "sitting" in this corner, resting his underside on the sand.
He seems fine otherwise, and is eating well (although not as "mad" as he used to up until a week ago, he used to go mad when I put food in, but he's still eating fine). Water parameters are all good.
The only thing I've changed in my tank in the last week is the lighting, I've upgraded it to 2 x T5 39W bulbs (from 1 x normal 25w bulb that I had on my old goldfish tank!). Other than that, nothing has changed.
, my cleaner shrimp and fire shrimp molted yesterday, and my fire only molted 10 days ago (first time my cleaner has in my tank). There's nothing else in the tank.