From what I saw in the video it didn't look like blood to me. I don't know what else it could be though... And no blood on the paper towels is a good sign!!! And I have the same issue with crickets climbing behind the background! I have been meaning to stuff something in there so the crickets cant get in. Anyhoo, I saw that you have your frogs in the 8"x8"x12" Nano tank. You will need to upgrade to the 12"x12"x18". Those Nanos are too small for a frog.