Why does my BTA keep hiding under rock?!?

[Vettitude]

I have had my BTA for about 6 weeks. About 2 weeks ago, it started moving and found itself a home underneath the rock that it came on. I thought maybe my lighting was too bright compared to the LFS (4x54 T5), so I left him there thinking he would eventually come out.
About 3 days after he went under the rock, it split. 1 piece looked sick. The other piece looks really sick. On Saturday, I decided to flip the rock over to get them back into the light. I lowered them in the tank as well, thinking they were getting too much light. Today, the sick looking one has moved back under the rock. The really sick looking one is just barely hanging there looking...well really sick.
My water parameters are ok. No trates, trites or ammonia. Ph 8.2. Temp 79'ish. Medium flow. Doesn't whip around but does get some indirect movement. Had it higher flow and lower flow. Higher ip in the tank and medium level in the tank.
Does anyone have any advice on what to check or what to do? Is the really sick one, too far gone?!?
Thank you

 

[Leedowlrods]

That sounds strange the poor things. They've got great colours too.
Sorry I've not got the answers

 

[Vettitude]

The really sick one is gone. I doubt he pulled himself into the rock he was on because he was barely hanging on. Weird thing though is that I have continually checked my ammonia levels and have always been at 0. Would something have eaten him? Maybe he had gotten so small, the ammonia level wouldn't have risen as much as I would have thought.
The other one has gone completely back under the rock again. They need light right? So why would it be hiding? Should I try turning it over again and lowering it in the tank? It is at the top 1/3 of the tank now.
Anyone with similar experiences?
Thanks