How to Sex Red Cherry Shrimp (telling the boys from the girls)

Red Cherry Shrimp are without doubt the most popular freshwater invertebrate in the hobby right now.

Eating Daphnia
Eating Daphnia

Part of the reason they are so popular is thanks to the ease with which they can be bred. Even the newest of Red Cherry Shrimp keepers can turn a handful of shrimp into a thriving colony within a few short months.

The main ways to sex Red Cherry Shrimp are color (females are generally more colorful than males), size, (females are generally larger than males), and by looking for the saddle (developing eggs) which shows itself as a golden patch on the back of the female Red Cherry Shrimp.



How to Sex Red Cherry Shrimp?

If you hope to breed your Red Cherry Shrimp, there is one inescapable fact, you will need at least 1 male and 1 female!

Telling the boys from the girls is an essential skill which, with a little practice, can help us easily identify which are the male Red Cherry Shrimp and which are the females.

The main ways we can sex our Red Cherry Shrimp are;

  • Color
  • Size
  • Abdomen shape
  • Pleopods (swimmerets)
  • Saddle/Eggs

Color

Color is my ‘first glance’ method for sexing Red Cherry Shrimp. Although not a 100% certain method, generally speaking, in the world of Red Cherry Shrimp, it is the females that have all the color.

Almost every time you look at one brightly colored Red Cherry Shrimp and one less colorful one, the chances are the brightly colored one is the female.

Color is not a 100% reliable method as Red Cherry Shrimp color can vary depending on whether or not the shrimp are under stress. Stress can bleach the color from a Red Cherry Shrimp. Also, in some color lines, the males also have color. The Bloody Mary strain for instance was developed with the introduction of the Chocolate Shrimp, meaning the males have bright colors too.

Male Red Chery Shrimp

Male

Female Red Cherry Shrimp

Female

As I say, color is not a foolproof method of sexing Red Cherry Shrimp. I have seen brightly colored males and drab, almost colorless females. However, it is a good indicator, and if you are buying a batch of say 10 Red Cherry Shrimp, buy 5 bright ones and 5 less bright ones and there is a good chance you will have at least one of each sex.


Size

Size is another indicator of whether or not Red Cherry Shrimp are male or female. Generally speaking, female Red Cherry Shrimp are larger than male Red Cherry Shrimp. The females will grow to around 1″ (2.5cm) long, whereas the males usually grow to about 2/3″ (1.5cm).

The problem with using size as an indicator of sex is, you might not know if the two shrimp you are comparing are the same age. As shrimp age, they grow. It is perfectly reasonable that you might be looking into a tank and seeing a small, immature female shrimp standing next to a full-grown male shrimp. You could easily confuse the two for being the opposite sex.

Size, when combined with color, does become more reliable. as a general rule, shrimp color improves as they grow, so there is a good chance a larger, but less colorful shrimp is a mature male, whereas the smaller, but more colorful shrimp is probably an immature female.


Abdomen shape

Abdomen shape is a fairly reliable indicator of the sex of a Red Cherry Shrimp.

Female Red Cherry Shrimp has an underbelly (abdomen) that appears to be much more swollen, especially along the bottom. The males on the other hand tend to have a much straighter underbelly.

The image below demonstrates how the underbelly is swollen

If you imagine cutting a Red Cherry Shrimp in half across the width of its back, the cross-section of the female would look like a capital letter D, but laying on its side.

The cross-section of a male Red Cherry Shrimp would be a lot more square.

Example of female Red Cherry Shrimp abdomen cross-section

Abdomen shape is a fairly good indicator of Red Cherry Shrimp sex. You don’t actually need to cut your shrimp in half of course, just observe them and see if they have rounder, more swollen abdomens.


Pleopods (swimmerets)

Red Cherry Shrimp bodies are divided up into 6 separate segments. The first 5 of these segments each have a pair of appendages which are called pleopods. These appendages are shaped like small paddles and are often referred to as swimmerets.

The shrimps’ swimmerets have evolved to help them swim through the water. However, they also have a secondary use.

In male Red Cherry Shrimp, the first pair of swimmerets has evolved to be used during the transfer of sperm between the male and the female. With female Red Cherry Shrimp, the swimmerets are used to continually fan water over the developing eggs which she suspends beneath her body.

Sexing Red Cherry Shrimp by looking at the differences between the swimmerets is an expert-level way to sex the shrimp, and not necessarily something that can be done just by looking at a tank full of Red Cherry Shrimp.



Saddle/Eggs

In my opinion, this is the easiest and most reliable way to sex Red Cherry Shrimp,

Essentially, female Red Cherry Shrimp develop the eggs in their bodies (this is known as a saddle) and then suspend them beneath their abdomens. Males do neither of these things, so if you see the saddle or the eggs, you know you are looking at a female Red Cherry Shrimp.

The image below shows two female Red Cherry Shrimp, both of which have a saddle. This saddle is the eggs developing inside the Red Cherry Shrimps body. As the eggs develop they move further down the body until they are ready to be passed out of her body and beneath her abdomen.

Once the female has passed the eggs and a male Red Cherry Shrimp has fertilized them, she holds the eggs underneath her body whilst they develop.

The image below shows a female Red Cherry Shrimp holding a clutch of eggs.


In Conclusion

I believe looking for the eggs, either internally or beneath the female is the only 100% true way to sex Red Cherry Shrimp without having to remove the shrimp from the water and examine it under a microscope.

When you are trying to establish if an individual shrimp is male or female, ask yourself the following questions;

QuestionYesNo
Is the shrimp brightly colored?Probably femaleProbably male
Is the shrimp about 1″ (2.5cm) long?Probably femaleProbably male
Does the shrimp have a swollen abdomen?Probably femaleProbably male
Can you see either a saddle or eggs below the shrimp?FemaleProbably male

About the Author

I’ve been keeping, breeding, and showing tropical fish for nearly 30 years. Over that time I’ve done it all! I’ve had great success and I’ve made some really foolish mistakes (like the time I bought an Asain Walking Catfish). Read more…
Richard James
Editor