Instructions
Watch the behavior of the gobies as they grow larger. If they start to attack one another, you probably have two males.
Locate the genital area in front of the anus. Both males and females have a tube called a genital papilla.
Look at the size and shape of the tube. The male has a longer pointy tube, while the female has a short, blunt tube that is yellow.
How to Tell Male & Female Dragon Gobies Apart
Dragon gobies are extremely difficult to sex visually, and successful breeding in captivity is rare. However, males can become territorial as they mature, so if you want to keep more than one adult, it's best to keep a single male with a group of females. Dragon goby is one of the common names of the species Gobioides broussonnetii, along with violet goby and Peruvian goby. This goby grows up to 3 feet in length and prefers brackish or salt water.