I long ago gave up trying to keep any of my fish's fins looking nice. As long as they aren't infected, I don't care if they're ratty-looking. >.>
Nothing spawns for me. Not even mosquitoes. Sigh. But watch, one of my rats will turn out to be male and I'll wake up to a surprise litter or something horrifying like that.
At least they spawned. Mine wouldn't even do that much. But cool if you got a bunch of baby panda cories!
Eggs that are viable are clear. Eggs that are opaque and white are fungused. In warm enough temps, the eggs should hatch in 3-8 days, with apparently 4-5 being the norm. According to this corydoras catfish book, it's suggested to add aeration for the eggs and a fungicide. And to avoid bright lights. On the other hand, thousands of cories have hatched in home aquariums without any such steps being taken so I wouldn't worry too much.