hello! on February first, I acquired a sack of California newt eggs. When I got them the sack was very clear, and I could see the little brown dots that were the embryos. About a week ago they started to elongate and look more tadpole like, and not like little circles. A few days later, they started to move and wiggle a little and would completely turn around in their eggs. But in the first couple days of them elongating in the egg, I noticed one side of the sack had a little fur like mold on it. I didn't want to disturb the eggs, so I left it alone and kept an eye on it. About when they started moving, the mold got bigger and I decided to investigate. I used feeding tongs to gently pry at the mold, but nothing happened, it didn't come off or anything, so I left it alone. The day after they started moving, I came to check on them and they haven't moved since. This was about 5 days ago, and since then the mold has spread to most of the sack and it is very hard to see into it. It looks like the embryos have grown a little bigger, but nothing other than that. this afternoon when I went to look at them, I noticed a brown spot on most of the embryos in the eggs. Some of them still resemble circles rather than tadpoles, but I didn't see them since they were behind the others. They are in a 10 gallon tank with about 4-5 inches of cold water, and I do a water change every few days, very carefully to ensure it doesn't bother them. There are a few rocks but it its bare bottom with nothing else living in it right now. The water I use is either collected rain water or water that has been treated and dechlorinated. I have raised frog tadpoles with no difficulty, what changed with the newts? Are they dead?