I've been counting larvae every day and the number that I could see in the tank was always somewhere around 23 larvae so I was estimating I had 30 larvae. Several days ago when siphoning the tank I sucked up 5 dead larvae, and still counted 23. The next siphoning, I sucked up 5 dead larvae again, and again still counted 23 larvae. The live larvae did not look 100% good to me and I started to worry about the deaths. I went to check the tank and with the water a little clearer than normal and I saw 10 dead larvae on the bottom! So I did what any professional larval culturist would do and I FREAKED OUT!!
I slowly scooped out each larva into a holding tank. Then dumped and cleaned the larval tank and carefully moved all the larvae back in one by one. I felt like I might lose all the larvae by handling them this way but I also knew I would lose them if I didn't make a change.
In moving the larvae I counted 58 and only one died the next day. :)
Here's a video taken today of a 20 day old P. venusata.
If you have difficulty watching the video here, try it here