Today the P. venusta are 50 days old and I moved them to a clean tank.
I was able to get a good look at each larva as I moved them one by one in a beaker.
Here is a video of the last one moved.
Most of the smaller larvae have died as they have not progressed in size or development over the last couple of weeks. There are now 17 larvae left. One is smaller than the others and has buoyancy problems off and on. The other 16 look great. About half of the larvae have pigment though most of their dorsal spines and fin as you can see in the video. I saw this in the Genicanthus watanabei just before they fully settled with juvenile colors so I'm hopeful that metamorphose will come soon.