Gulfstream's Fungus-Ease is a liquid water additive that will treat fish with fungal infections. Fungal infections are very common, normally causing small cotton-like protrusions anywhere on your fish's body. Mouth fungus is considered a bacterial illness, as well as fin, tail, and general body deterioration. These symptoms should be treated accordingly. Be sure to follow directions closely when using Fungus-ease to ensure your fish's rapid return to health.