Fish Monitoring System Is Essential Because Many People Love To Grow Fishes As Their Pet In The Home. In Our Day-to-day Life, It Is Difficult To Monitor The Aquarium Tank Regularly. As A Consequence, It Causes Mortality Of The Fishes. The Quality Of Water Might Be The Main Issue. It Mainly Depends Upon Parameters Such As Carbon, PH, Temperature, Turbidity, Dissolved Oxygen, Etc. To Maintain These Parameters, Various Sensors Are Used In The Fish Monitoring System. This Will Increase The Production Of Fishes And Decrease Mortality. Many Researchers Had Proposed Various Methods For Maintaining The Water Quality In The Aquarium And The Fish Ponds. The Main Purpose Of This Paper Is To Review The Sensors Used In The Fish Monitoring System.