Freshwater Aquarium Shrimp Reproduction
An explanation of the reproduction process
The Freshwater Aquarium Shrimp has a unique reproduction process of which some aspects are unknown. What is known can sometimes be skewed or misunderstood. This article is meant to try and fully explain as much as possible the reproduction process of the Freshwater Aquarium Shrimp. This article is meant to explain the process for shrimp which do not have a larval stage during reproduction. This article pertains to those species which produce miniature adults directly from the egg during reproduction.
Of course when attempting to understand the reproduction process one of the most important aspects is the ability to sex the shrimp. However, this is not that easy. Some species are very easy to sex whereas others are virtually impossible to sex with what is known now. Species such as the Red Cherry Shrimp, Yellow Shrimp, Snowball Shrimp and a others are very easy to sex. Other species such as the Red Goldflake Shrimp, Cardinal Shrimp, Harlequin Shrimp and others can be extremely difficult to sex. Sexing really does depend on the species you are observing. Check out each species info page to read the detailed information on that particular species and how to sex it.
Age: Sexing of course depends on the age. Trying to sex adults is a lot easier than attempting to sex juvenile shrimp. Juvenile shrimp can be very difficult to sex, sometimes impossible depending on the size and species. Sexing sub-juvinile shrimp will most likely be impossible due to the fact that the shrimp is not old enough to display any gender identifying attributes, etc. It is definitely a good idea to only attempt to sex adults.
Size & Coloration: With many species the female is typically larger than the male. Also, the female is sometimes darker or more robust in coloration. As with the Red Cherry Shrimp, the female is not only larger but a much darker red coloration. The male Red Cherry Shrimp is instead almost colorless at times and much smaller. Females of some species may also display a line down their backs. Below is a photo of two Red Cherry Shrimp, one male and one female. Notice the size difference and more importantly the difference in coloration.
Gender Attributes: There are also other methods to easily sex a shrimp. Certain identifiers, or attributes, can differentiate a male from a female without question. These attributes typically involve the female and certain aspects of her anatomy that do not appear in males. Some of these attributes also occur at certain periods whereas some with appear at all times. Of course a female currently holding eggs will tell you that it is indeed a female. However, when eggs are not present there are other ways to tell.
The "Saddle": Once of the most common and distinguishable attributes is the appearance of a "saddle" or miniature undeveloped eggs in the ovaries. The term "saddle" comes from the fact that that the undeveloped eggs appear on the back of the shrimp, behind the head, which looks like the saddle on a horse. Below is a photo of the Yellow Shrimp with both eggs as well as a "saddle". Notice in the first photo how the "saddle" actually looks like a real saddle you would find on a horse. In the second photo notice the tiny undeveloped eggs that actually make up the "saddle".
Curved Underbelly: Another way to tell the difference between a male and a female is the appearance of a curved underbelly, or the region underneath the tail. When the female is pregnant the underbelly acts as a defense against potential damage to the eggs. The curved underbelly appears in females of many species of shrimp but there are some species which do not possess this characteristic regardless of sex. The lack of an underbelly does not necessarily mean that the shrimp is a male. It really depends on age and more importantly the species of shrimp in question. Below is a photo of a Crystal Red Shrimp Female with a distinctive curved underbelly.
The "Act": Mating between a male and female shrimp happens extremely fast. In a matter of seconds the male latches onto the female abdomen to abdomen, deposits his sperm, and quickly then releases the female. Sometimes you can actually observe a male constantly harrassing a female in an attempt to grab onto her. Next time you think that the shrimp are fighting it may be a male trying to mate instead. Below are a couple of photos of a male Red Cherry Shrimp latched onto a female and depositing sperm.
Fertilization: As discussed earlier in the article the female contains tiny undeveloped eggs in the ovaries, also known as the "saddle". The male deposits the sperm into the female before the eggs are passed from the ovaries and into the undercarriage. As the eggs are passed down into the undercarriage they become fertilized by the previously deposited sperm. There is a big misconception that the eggs are fertilized after they appear in the undercarriage which is untrue. You will not see a female mate if eggs are present, you will only see a female mate when eggs are not present. It is believed that the male has a tiny "appendage" that it uses to deposit the sperm into the female. Below is a photo of the "appendage" as well as a zoomed photo.
Unknowns: There are many unknowns as to the exact science behind the mating process. It is believed that shortly after molting the female is ready to mate. The way in which the male knows that the female is ready to mate is unknown. Perhaps she releases a chemical signal or some other type of notification that only shrimp can detect. It is known though that when a female molts the males in the tank will swim around the tank in a drunken manner looking to find the ready female. When you see a bunch of shrimp swimming around in the tank against the glass make sure to sex the shrimp first. If you look closely you may notice that they are all males. If that is the case then everything is ok, they are just looking to mate.
Berried: A female shrimp is of course officially pregnant when the eggs are present. Sometimes the term "berried" is used to signify that the female is holding eggs, the eggs being the "berries". As stated before, once the eggs are present then they are officially fertilized. If the eggs have not hatched then the baby shrimp is not fully developed. If eggs have been dropped or it appears that the female has lost some eggs there can be many reasons for this. Some believe that young females that become pregnant for the first time are "amateurs" and will tend to drop some eggs. Others believe that when a female is unhealthy or unhappy then she will also drop some eggs. Also, it is believed that the older a female becomes the more eggs she can carry. All of these theories may be true. It is known though that when the conditions are right and the female is happy then she can constantly breed around the clock, hatching and once again becoming pregnant a few days later.
Egg Development: Egg development all depends on the species of shrimp. Some species will hatch their eggs sooner than others. Also some species hold more eggs than other species. Egg coloration is also different between species. It is recommended that you view each shrimp species information page for the specific shrimp that you are inquiring about regarding egg development, clutch size, coloration, etc. There are a few species that you can actually determine whether hatching is near. Most of the time when a female is holding eggs and a "saddle" appears this is a good indicator that the eggs are close to hatching. However, with some species you cannot see the saddle even if it is present and in some cases a "saddle" may not appear even if the eggs are near hatching. Another much simpler way to identify whether a species is near hatching is the appearance of the eyes of the baby shrimp still inside of the egg. Eggs with eyes are a great indicator that hatching is days away. You may not be able to see eyes with some species of shrimp. Below is a photo of both Yellow Shrimp and Snowball Shrimp eggs with eyes appearing.
Newborn Shrimp: The actual hatching of the shrimp is extremely fast. The baby shrimp seems to pop out of the egg in under a second and latches onto the first thing it can find, typically a plant like moss. People that have observed the actual hatching say that the baby shrimp seem to fly out of the belly of the female. Some have even said that the female seems to assist the babies out by "kicking" them or giving them a nudge. It is very rare to observe the actual hatching of a shrimp. The females tend to hide and the hatching may even occur at night. Below is a photo of a newborn Red Cherry Shrimp.
Hatching Photos: Luckily once again Peter Maquire was able to pull off his magic and capture this rare moment. The photos are posted in the article Red Cherry Shrimp Hatching. Below are a couple of the photos but please go to the article for more.
Artificial Hatching: Believe it or not you can actually hatch shrimp eggs without a female. One day you may find a dead female shrimp that is still holding eggs. It can be a depressing sight because those numerous eggs each equal an unborn shrimp. However, you can hatch them with a few very simple steps and some delicate care. All of the information you will need to know can be found in the article Artificially Hatching Eggs. It is highly recommended that all shrimp breeders at least read the above article. You may never know when you will actually come across a dead pregnant female shrimp. It is very simple to do and does not take a rocket scientist at all.
As more information is gathered this article will be updated. If you feel that something with this article needs to be added or changed please contact us!