The photo shows a female of Nile tilapia, Oreochromis niloticus based on her papilla. For smaller sizes and/or with personnel who are not familiar with tilapia, a dye named as crystal violet may be used to show clearly the papilla.
Note: We decided not to watermark the photos in order not to upset its clarity. However, we trust you will notify us if you wish to use a picture or more. This will be appreciated.
