This article is transferred from the ifish aquarium ornamental fish
Pictured| Wild Peacock Fish Male Fish in Jemez. The population here is suspected of being released decades ago by tourists into hot springs to control mosquito breeding
Brief introduction
Located at 2,240.28 meters above sea level, the Jemez Mountains in Sandoval County, New Mexico, are one of the most unique and oldest wild populations of peacock fish (Poecilia reticulata) in North America. This self-sustaining peacock fish population is not only a treasure for lovers of oviparous medaka, but also the focus of officially published research.
As with most hot spring environments in the United States, conditions here can provide an oasis for species that evolve in tropical environments and avoid harsh seasonal climate fluctuations. Overall, the size of the habitable range is usually limited by temperature, predator, and water quality parameters in the first few pools near the heat source. In other habitats, it will extend downstream to the lowest point of the winter viable temperature.
Although published studies have shown that "mosquito-eating peacock fish" were stocked around 1975 or earlier, There is more than one source of peacock fish in Hermez, suggesting that the earliest points in time were between the late 1940s and 1960s. This is consistent with most North American wild populations. (Editor's note: The area has long attracted tourists to its hot springs; the purpose of wild peacock fish may be to control mosquitoes).
Based on known genotypes and morphological manifestations, the Hermez population is unique because modern peacock fish strains rarely appear in individuals. While may not be wild-collected, they rarely show signs of being domesticated. Because their introduction has become an interesting population study object for researchers and breeders.
Pictured | male Hermez wild peacock fish
Environmental conditions
Previously published U.S. Geological Surveys showed that McCauley Springs had water output between 310-400 gpm. The same study shows that the average emission temperature is between 30.6-31.6 °C. Conductivity ranges from 160 - 180 S/cm.
Analysis of tritium levels at Macaulay Springs shows that the springs entered the ground before 1953, although it is also implied that some springs entered after this point in time. The springs circulate in the moat of the ancient Valles Caldera, 1,500 feet above, and are heated by geothermal energy common in the region. Although many of the area's springs are hotter, Macaulay is generally considered a "hot spring" diluted by groundwater, with a pH of 8.0 and a relatively low mineral content for most.
My Hermez study population was taken from individuals collected in large numbers on July 15, 2016. The peacock fish habitat is mainly limited to the first two pools after the discharge of the hot springs. Large numbers of peacock fish and Largespring Gambusia (Gambusia geiseri) inhabit the first and second pools. The average depth of the center of the pool is about 3 feet. The water flowing from McCauley Springs flows into the East Hermez River and then into the Hermez River. At the time of collection, the water temperature at the spring was exactly over 32.2 °C, and the pH was slightly higher than 8.0. The water temperature of the first habitat pool exceeded 31.1 °C, and the water temperature of the second pool decreased significantly. Each pool has a different size of sand and rocks. In the first pond grows abundant plants and algae similar to Najas guadalupensis, while the lower ponds lack vegetation.
The water temperature in the pond is considered to be within the "adaptable range" of peacock fish, although it is close to the upper limit. Extreme water temperatures are not necessarily "fatal" immediately, but can lead to undesirable consequences over time. Male peacock fish have been shown to favor slightly lower temperatures (24.5 °C), while females have 28.2 °C, which is the optimal developmental temperature for their secondary sexual characteristics such as body color and genitals (gonopodia). Lower temperatures can delay ripening, while higher temperatures can cause the body to deform. Further research supports that long-term rearing of individuals above 30°C leads to a decrease in body weight, growth, reproduction and athletic ability.
Pictured| Macquarie Hot Springs Pool. Photo courtesy of Tom Coggins
Just as temperature limits these wild populations, so does predation. Predators in the first two pools of Macaulay were limited to non-native Geysse mosquitoes, birds, crustaceans and insects. Common mosquito-eating fish (Gambusia affinis) known to exist elsewhere greatly limit the population of wild peacock fish juveniles. The longnose Dace and fathead minnow, Pimephales promelas, native to the East Hermez River, are located beneath the restricted peacock fish habitat.
Observation of phenotypes
The fish collected showed no signs of parasite infestation, nor did they appear in the offspring that followed in captivity. This population may still retain a resistant genetic constitution. A further benefit is achieved at a constant high water temperature of more than 28.9 ° C, which is fatal to Ichthyobodo necator / Costia. The individual roughly coincides with the description of the study published by Nicoletto and Kodric-Brown (see: Excerpts from Scientific Studies). In general, individuals in the collection and F1 offspring are decorated with some orange reflective spots.
Pictured| male Hermez wild peacock fish in foraging
When there are no predators in the nursery tanks, the captive-bred F2 and F3 males are more red and yellow as expected. The spots are very pronounced, and the round spots are surrounded by an aura of iridescent (crystall) cells. In addition, it is noted that the top and bottom swords are also more extended.
Almost all of the males and their offspring collected have transparent dorsal fins. Some show black markings on the back, but not the traits described by geneticist Øjvind Winge as maculatus (spots). Most males show basic wild-type oval tail fins, with the rest being primitive flag-tails. Highly reflective iridescent cells surround the black "eye spots" in front of the body; the blue reflective pattern is present in almost all males, including the long bands.
Pictured| Hermez wild peacock fish male fish
Potential temperature extremes manifest themselves in two forms in collected individuals: size and shape. Both sex sizes collected at Macaulay Springs were significantly smaller. However, this is not fully evident in F1 offspring raised at cooler temperatures. At optimal temperature and feeding regimens, males and females increased in size significantly. While the size differences between sexes still exist, the overall size of females increases proportionally.
A high proportion of the collected females show shorter bodies, possibly due to the high temperature environment in the first pool. This "short-body" pattern has slowed down in captive-bred individuals, although in general the short-bodied type of female fish is much larger than many wild or captive breeding populations. The males are the opposite. The collected males exhibit an "elongated" appearance, albeit with slower water flows, while captive-bred fish are thicker. In general, males and females increase overall in size and length.
All fish appear to be heterogeneously joined or homogeneous combinations of purple mutations (Pb). It lives longer than some wild populations that I and others have raised. Studies have shown that they have progressively developed a feeding habit consisting mainly of algae in limited predators. The body has round and striped markings, mainly the latter. Reproductive capacity is significantly better, with about 15-30 medium-sized fry being laid at a time. Judging by the reproductive results, the population shows few signs of additional introductions from other sources since the beginning of stocking. All research papers seem hesitant to compare the stocking time introduced earlier in the late 1960s and 1970s. From my informal collection and observation, an earlier stocking date seems possible.
A portion of the males exhibit "back reflective spots" formed by crystalline (iridescens; Ir) cells, indicating that their stocking dates are earlier. Iridescent cells were found in the fish tanks of early breeders in the 1920s-40s, and long before the modern-day Andros peacock fish (Poecilia reticulata wingei; Endler's Livebearer).
Pictured | rainbow male with a reflective spot on the back
All females have colored caudal fins/oval tails, except for limited violet-blue iridescent luster and/or yellowing variation in flaves (Fla) forms at the base of the caudal fin. Compared to many other wild populations, females perform well in reflective color, as are found in males. These include a purple-blue iridescent glow, pronounced reticulations on the body, and black stripes along the shoulders to the lateral line.
Pictured| Female of the Hermez wild peacock fish
Surprisingly, this population does not exhibit a very pronounced "startling or jumping" response to human traffic or activity from above the water surface, and often surrounds the bather in groups. At high temperatures, this increase in mobility may symbolize fewer predators in adult fish (the predation of Geysseids is limited to juveniles) and/or low satiety levels in the population as a whole (limited food resources in small areas). The collected individuals easily adapted in high-water-level fish tanks without caps. Interestingly, when they were moved in and confined to small tanks during filming, males that showed a near-wild color appeared highly restless and scurrying around, as opposed to artificially bred individuals whose body color increased due to the lack of predators.
Excerpts from the study
Kodric-Brown (1989) used 2 study populations, the Parea Wild Type (from Trinidad) and the Hermez Wild Type (McCauley Springs, New Mexico). Compared to other populations, wild fish in Macaulay Springs have fewer orange spots. This is not surprising , as " females from the Hermez population have reported significantly different preferences for male individuals " . Hermez males have more iridescent spots (blue and white) and more black round and striped spots. Hermez males are very shiny purple-blue, usually showing an iridescent luster.
The wild-type peacock fish used in this study are the third generation of wild populations from the Macaulay Hot Springs in the Hermez Mountains of New Mexico. This population has been around for at least 16 years. All the fish only seem to be in good physical condition. The three male tail types used are the top sword, the flag tail and the round tail, which are common at Macaulay Springs.
Alan S. Bias has been a breeder and demonstrator of peacock fish for 47 years. For more than 30 years, he has focused on a strain known to breeders as the "sword-tailed peacock." For nearly 20 years, he has completed cellular-level studies that combine systematic reproduction experiments and systematic observations to help breeders understand the complexity of modern peacock fish genetics.
This article is compiled by: Long Crawl
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