Amphibian eggs are different than amniotic eggs. They lack an outer shell that you find in bird and reptile eggs. Frogs and salamanders are the most common type of amphibian. These eggs require a water source to stay hydrated and properly oxygenated. The female lays her eggs in the water and then the male deposits his semen. The eggs are usually encased in a jelly like substance to protect them from bacteria and mold. The fertilized eggs then incubate in the water pool until they hatch into tadpoles.
Amphibian breeding programs utilize a thermostatically controlled aquarium for egg incubation. One end is heated with an aquarium heater while the other end is cooled using a chiller. Foam sheets insulate the outside to maintain the proper linear heat gradient. The water in the aquarium is supplied with fresh oxygen via an airstone. The egg clutches are suspended over the tank inside porous baskets to simulate the natural environment. Temperature requirements vary by species, however 100% humidity is required to keep the eggs moist.