I have about 40 bubble tips in two different tanks. Have had them for years. I have found the only time they really move is if they are stressed from water condition. Lighting doesn't seem to be a big issue. They do need good light, don't get me wrong there. That's how they produce food. I run LED in both tanks and they are fine.
The problem I have had in the past is when the diatoms have an outbreak(due to many reasons) they will ball up and look like they are dying. they will start to walk to try to find better place. I would turn your lights off for about 3 to4 days, do a water change, suck out any brown diatoms on the sand(don't stir up the sand too much). They are hardy guys and should bounce back after your water gets better.
You can feed them chunks of meat, but they really don't need any supplemental feeding. My skunk clowns love these guys-they go into all of them. my pair of Percula clowns in the other show tank do not leave the same bubbletip ever.