<p>Fish is a great food to consume as it is nutritious and delectable, but has very limited shelf life. Consuming the fish after that short window of time can damage people’s health. In this work, we have developed an application software to determine fish freshness by dint of images recorded using a Smartphone camera. The captured images of fish gills are processed by the Smartphone application software where at the backend image processing algorithms are incorporated to determine qualitative measurement of freshness index. Experimental results demonstrate that the developed application can effectively determine the freshness level. The proposed application is based on colorimetric changes associated with freshness level of the fish samples, has the potential to improve the safety of fish products and to help consumers make informed decisions instantly about the fish they purchase.</p>