Hi Eli
Gas bubble disease is a noninfectious syndrome seen in aquatic frogs when the water is supersaturated with gasses such as nitrogen and argon. Symptoms include buoyancy problems, very tiny bubbles in skin and foot webbing, hemorrhages, and loss of mucous coat. Generally most frogs will recover when the water problems are corrected. However, recovered frogs may not be ideal for breeding.
How do I know if the water is supersaturated? Look for tiny bubbles in the water or sides of the tank. The color of the water may turn milky-white. Excessive nitrogen can cause health problems.
How do you correct the problem? The water must be degassed. It is the process that creates a large interface between water and air. This is achived through the process of aeration (mixing water and air). Air stones or low-output filters are used to increase the water-air interface that allows the gasses to escape to the atmosphere.