How do you know if fire belly toad eggs are fertile?

To determine if fire-belly toad eggs are fertile, look for signs of development such as a dark spot or eye within the egg, indicating an embryo is forming. Fertile eggs are usually firm and transparent, while infertile ones may appear cloudy or have a discolored appearance. Additionally, observing the eggs over a few days can help; fertile eggs will typically show signs of growth and change. If the eggs don't develop or show no signs of life after a week, they are likely infertile.