There are anatomy differences between the male and female volcano shrimp. But due to its small size and quick reflexes, you will lose the shrimp in seconds. Or you can bait them with food and use a magnifying glass to observe them. Luckily, I learnt a trick to locate the female shrimp quickly.When the female volcano shrimp is matured and ready to breed, the eggs sac behind the head will turn black.The female shrimp has a more vibrant red colour than the male. Fertile and mature female volcano shrimp with an eggs sac behind the head On the other hand, male volcano shrimp don't have an egg sac.Males are mostly white, yellow, spotted pink or translucent in colour. Their body are more slender and the claws are bigger than the female.Due to the small size, it's almost impossible to see. Male has a slender body and look translucent or pale white. But if the shrimps are scared or disturbed, it will lose its colour immediately.Both sexes become translucent and identical for hours.You will need to wait for them to calm down before you can sex them again.