A 75 gallon is really the minimum size tank for a breeding pair. In fact many breeders will tell you that having larger gallon tanks helps minimize aggression between partners. But luckily, you don't seem to be dealing with aggression issues with your pair. So she hasn't laid eggs yet, no big deal, increase their feedings and keep up on water changes. Increase feedings, especially with frozen bloodworm. Some females lay eggs once every few months, then others lay every 10-16 days. Each female can be different with their egg cycles.
