Have you lost fish in your pond or aquarium? If yes, it may be due to Nitrite Poisoning. Nitrite Poisoning includes symptoms such as ‘piping’ or gasping at the surface, listlessness, and rapid gill movement. When the fish dies, its gills will be flared and you may notice dark brown or blackened patches under its skin. Nitrite Poisoning or toxicity in fish is referred to “Brown Blood Disease”.
When you suspect Nitrite Poisoning, is killing your fish, perform a 50-75% water change and perform a thorough tank / filter media maintenance. For long term fish care, perform weekly water changes, monitor water chemistry and change filter media as directed.