This video is of a wonderful family of Harlequin Shrimp we found recently. There is Junior, who is determined to get his bit of yummy starfish food, dad, looking proudly on and pregnant mum.
These shrimp are the 'royalty' of the Crustacea, and this is good paparazzi footage of them 'at home'.
Junior is obvious to spot. He's the tiny one. The difference between the male and female shrimp is easy to see in this video, as the female is pregnant and 'fans' her eggs from time to time, to keep freshly oxygenated water flowing over them.
You can see that the female has a much wider abdomen, and this is where she keeps her eggs. This is true with most crustaceans and one of the ways we identify sex and can tell, from the fanning action, if they are pregnant.