from wild type to the Full Blue Rili. Neocaridina heteropoda.

The various captive-bred forms of Neocaridina heteropoda are very popular with “cherry shrimp” fanciers, who are often baffled by the names and histories of the many different strains. Here we trace how the Sakura strain has emerged from the Taiwan wild type and look at what is going on with the “Jelly Blue” strain.

Steffen, a friend and professional breeder, visited me to pick up some breeder tanks with gauze bottoms for his Cambarellus patzcuarensis Orange and Crystal Red shrimps. On that occasion, he brought along offspring of a wild-type strain of Neocaridina heteropoda. He handed me the bag of shrimp with these words: “I received these animals from Friedrich Bitter, who brought them back from Taiwan. They occasionally produce red individuals, from which the Sakura supposedly originated.”

Wild-type strain from Taiwan

Steffen had selected the darkest animals. Females showing a dorsal stripe were the most intensely colored animals. They were almost completely black, but with a more or less distinct blue tone.

The males’ pigmentation was much fainter. They had black and brown vertical stripes on a transparent background, which did not look particularly attractive. Steffen told me that the demand for these animals was not very high, but as killifish food they were first class!

The animals were very productive, like almost every Neocaridina heteropoda variety. However, it took about three months until I discovered the first two red shrimp. Of course, they were both females. After half a year, I had a total of five red shrimp. The three females were solid red, while the two red males showed a vertically striped pattern. These animals formed the basis for further breeding.

The females of the F1 offspring were indeed red, similar to the Sakura, but the color was moreof a reddish brown. The males all showed vertical red to reddish brown stripes on a transparent background. Further selective breeding improved the colors significantly.

The red became more intense and brilliant, and the brown tinge disappeared. In the course of further breeding, even the color of the males improved. They lost the striped pattern and became as solid red as the females. Of course, there were always some males who still showed a striped pattern.

My home-bred Sakuras and the Sakura imports from Asia shared two similarities: Among the offspring of both strains, females emerged with a brighter and pale translucent red coloration, males with a dark vertical stripe pattern. In the Asian strain, the proportion of these animals was approximately 5 percent. In the strain that I had selected, the percentage was much higher.

This might have been due to the fact that my strain had not been selectively bred for as long as the Asian strain, and therefore may not have been as stable. I also noticed another commonality: the offspring never produced animals with the wild-type pigmentation.

Later, backcrossing of a red female with a wild-type male produced only brown offspring. The red animals are therefore pigment-deficient mutants of the wild type. The red color is inherited recessively, while the wild type is dominant. I am now convinced that the Sakura strain was selectively bred from the Taiwan wild-type shrimp.

Sakura: the first strain I received the first Sakura strain several years ago from a fellow breeder. They were the offspring of the first animals imported to Germany. They were significantly more colorful than the Red Cherry strain, and even the juvenile shrimp were distinctly red in contrast to Red Cherry babies.

Among the offspring there were some females and a few males that showed a solid red color. The proportion of these animals was about 20 percent. The remaining animals were all nicely red but had small colorless patches on the abdominal and carapace areas. In the males, there were variations in the patterns. Some males had a more or less wide vertical striping pattern on a transparent background. The stripes of these animals showed a darker red than the red of the other animals. The rest of the males looked similar to the females of the Red Cherry, with colorless spots on the abdomen and carapace.

In the course of further selective breeding the number of Sakura (solid red animals) became greater. A dark opaque red covered the whole body. Egg-bearing females could only be identified by their corpulence, because the opaque red color of the abdomen concealed the eggs. After years of selecting, the proportion of solid red animals is now at about 90 percent, and I am quite pleased.

Soon individual orange animals emerged, but also red animals that met the “Rili” criteria with a translucent midsection. I maintained these “false color” variants further. The orange

Sakura was a xanthochromistic form, inherited recessively, and thus genetically stable. However, the red “Rili” was different. Here, the path to genetically stable animals was significantly longer.

It is noteworthy that after breeding thousands of offspring, I have never encountered a single black-brown wild-type animal among the original Sakura, orange Sakura, or red “Rili” strains.

Initially, I was unhappy with my Sakura because the photos on the Internet always showed animals with solid red colors. No individuals were ever shown that had the color pattern of the Red Cherry, as did most of my offspring. At the time, there were no Sakura available in the pet shops yet, so I attended different fish auctions and invertebrate meetings. It was in vain; the animals exhibited or offered for sale as Sakura all looked like my offspring. Some were even worse than mine.

Then the first offspring of some breeders appeared on the Internet. Most of the offerings were accompanied by photos. But even on the Internet, these so-called Sakura were just nicely colored Red Cherry shrimp. But when a seller offered imports from Asia, the photo showed a Sakura. Hence, real Sakura were only available from Asia at the time.

The proportion of female offspring was approximately 70 percent in all my Neocaridina heteropoda strains,whether they were wild forms or color varieties.

Among my 200 Sakura import animals there were just six males, and they were barely recognizable as males, because they were colored like females.

Since the male Neocaridina heteropoda captive-breds are generally less well colored and the Sakura undergo additional color selection by their Asian breeders, not many are exported.

I suspect the Red Cherry males were crossed into the first Sakura imports. This may have been because the Sakura strain was not as genetically stable yet or because few or no males were exported due to color selection. Perhaps the males were also screened out to maintain exclusivity as long as possible for this prolific shrimp.

Sunkist

I was pleasantly surprised when I first encountered the Sunkist strain, an orange Sakura from Asia. I did not expect such an intensity of color; my own orange strain, selected from the original Sakura animals I had received from a breeder, was yellow-orange and slightly translucent. The Asian Sunkist animals were bright orange-red.

I received 80 of these beautiful shrimp from Asia. They were all already 0.9-1.0 inch (2.2-2.5 cm) long, and most females carried eggs. Most animals had an opaque, bright orange-red color. Some animals showed an opaque yellow-orange. By contrast, the only two males among them were more yellow-brown.

However, the color of the offspring was a surprise.

Reminder: most females already carried eggs when I received them, so they were an original Asian strain. The colors of the offspring varied from transparent yellow to yellow-orange, bright orange-red, light red to light brown. The absolute highlights among the approximately 400 offspring were a green male and a black female that was already carrying eggs when I found her.

I moved the green male and the black female together into their own tank. The color of the offspring was not really a surprise for me—more a confirmation. There were five green animals, two yellow-orange, and the rest were divided evenly into bright orange-red and black shrimp. The black offspring suggests that the Sunkist strain is derived from the Sakura and is thus the Taiwan wild type.

“Full Blue Rili”

In the “Rili” strain, the red is interrupted by a whitish/ transparent stripe. I actually had ordered “Rili” from Asia, because I wanted to introduce new blood into my own “Rili” strain. But before crossing the Asian “Rili” into my strain, I wanted to wait for the first offspring to make sure I made no mistakes.

I received 80 beautifully colored “Rili” animals. Unlike with the Sakura and the Sunkist imports, there was an ample number of males among the “Rili.” The animals had a size of 0.8-1.0 inch (2-2.5 cm) and almost all females carried eggs. After my experiences with the Sunkist, I was looking forward to the offspring, and I was not disappointed!

The strain was very prolific and the 80 shrimp quickly turned into several hundred animals. As in the original animals, many F1 “Rili” showed a bright red color. However, there were animals in which the red color was darker and more towards black. Under favorable light, these “Rili” usually had a more or less distinct hue of blue in the transparent midsection. This blue tint was also present in some red animals. I therefore called these animals “Blue Rili.”

Among the females it was easy to recognize the “Blue Rili” because they carried a blue to blue-green egg spot. Later, the eggs also showed these colors. In the male sex, the “Blue Rilis” were mostly those animals with a darker red color. In the course of breeding, I realized that the red parts of the body in the offspring were becoming smaller and smaller. Thus, red Sakura had to be crossed in, since the “Blue Rili” never produced fully red animals that I could cross back to.

The strain was now almost stable. The offspring were divided into “Red Rili,” “Blue Rili,” and some black-brown wild-type specimens with a more or less distinct blue tinge. The continuous breeding had shown that the wild type was responsible for the light blue color of the “Blue Rili.”

Then, among the offspring, the first “Full Blue Rili” appeared, which showed a bright, translucent blue on the entire body. Some of the animals still showed a small red spot on the head.

Such light blue shrimps were imported from Asia and sold as “Jelly Blue.” I had hitherto believed that it was an intensely colored “Blue Pearl” strain, but I was proved wrong when I purchased some of these animals. They were clearly “Full Blue Rili,” since two of the shrimps still had the typical red spot on the head. Since these animals produced some Taiwan wild types among their offspring,

I assume that they were also derived from this wild form.

The “Rili” that descended from my first Sakura strain were all red “Rili” without a blue tinge. They were the result of the fact that I transferred all excess animals from the breeding tanks into a large aquarium and offered them for sale. Of course, these animals also reproduced, but without selection.

From my experience with breeding Guppies, I knew that under such conditions animals regress to the original form. That happened also with the Sakura. They started in the middle of the body with translucent colorless stripes that became wider and wider, until only the head and tail regions showed any red color. Later there were also translucent shrimp, including some that looked like wild type “Red Fire” males. If these transparent shrimp had not had a blue tint, they would have been “Jelly Blues.” But the way they were, they looked rather plain and not very appealing.

Among the “Rili” offspring from my first Sakura strain, I never found an animal with the wild-type color. However, since there were individual transparent animals that corresponded to the Red Fire wild type, it suggests that Red Cherry or Red Fire animals had been crossed in.

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