1. When breeding angelfish, it is normal for the first spawn to suffer heavy losses and not make it all the way to the hatching phase. You should have the proper equipment before you start to breed angelfish.
2. Avoid placing your aquarium near a radiator or any other form of heater. The heat given off by these devices can easily upset the temperature balance in your aquarium. Raised temperature levels can kill off the fish and plants that you have in your aquarium.
3. Make sure to always keep your aquarium level when placing it. If your aquarium is uneven, the weight of the water can press against the seems and this can cause major problems in your aquarium.