Sorry about your spawn. Hopefully they'll do better next time.
I breed in dark colored tubs without lights nor filters. In fact I often cover my tubs, just allowing enough light so my plants won't die. A good father will always maintain his nest/eggs whether dark or light. They are less active during the night and may neglect their spawns, but not for long. That's why (IMO) they need to be in full health to spawn.
On your next attempt, make sure (specially) the male is in good health - very active, as if tireless. Don't worry about the nest because some males are reluctant to make them. If he neglects his spawn again, you can brand him a bad father and try alternative methods.
@DormDrax: I'm sorry if I have offended you and anyone else with my remark. But sadly it's a fact that breeders would keep their best results and sell overstock/rejects. As a side note; I too work with rejects and work my way through to improve them.