The Black Bar Endler Strain has a prominent "Black Bar" on both flanks, creating a striking contrast with the other bright adjacent colors. Alongside the Black Bar, other prominent colors on the body usually include red, orange, & yellow (& occasionally green). Also, sometimes specks of blue, green & purple can be seen as well. Additionally, there is often a light blue patch under the dorsal fin and the tail usually displays a red / orange "sword and a half" outlined in black. The dorsal fin may be clear or occasionally display orange, red and black. Black Bar Grading Standards:
Grade A “Best in Breed”: The black bars are a bold deep black, thick / wide, and curve from under the eye to just under the dorsal fin in a relatively smooth curved line. The black bar is not broken and is relatively symmetrical on both sides of the fish (i.e., the bars on both sides of the fish match). The dorsal fin contains some color (not clear). The tail displays a thick black outline along most of the top and bottom of the tail. Next to the black outline is a strip of color, usually red/orange, with some whitish blue near the tips. They are also generally larger than grades B & C.
Grade B “Symmetrical”: The black bar is smaller and thinner than grade A and also may not be a deep black. The bar usually does not stretch all the way from the eye to just under the dorsal fin. The bar is not broken or globular, and is symmetrical on both sides of the fish. The dorsal fin usually contains some color. The tail normally displays a thin black outline along part of the top and bottom of the tail. Next to the black outline is a strip of color, usually red/orange, sometimes with whitish blue near the tips. They are also generally smaller than grade A.
Grade C “Standard”: The black bar is usually smaller and thinner than grade A/B and may not be a deep black. The bar usually does not stretch all the way from the eye to just under the dorsal fin. The bar is usually broken or globular, and may not be symmetrical on both sides of the fish. The dorsal fin often has no color. The tail displays some color, but usually does not have the black outline along most or part of the top and bottom of the tail. The color is usually clustered close to the base of the tail and does not extend to the tips. They are also generally smaller than grade A.
The Peacock Endler strain has a prominent black “Peacock” like spot on its tail which is a striking focal point that offsets the other bright colors on its torso. The top portion of both flanks are distinguished by a red / orange stripe (sometimes broken) and a black spot(s) below the stripe. Alongside the red / orange stripe and black spot(s), other prominent colors on the body often include yellow & green. Also, but rarely, specks of blue, green & purple can be seen as well. Additionally, the tail usually displays a red / orange bottom and or top “sword” outlined in black. The dorsal fin may be clear or occasionally display orange, red and black. Peacock Grading Standards:
Grade A “Best in Breed": There is a big bold deep black peacock dot on the tail. There is also at least one big round or oblong bold deep black peacock dot on the body. The sides have a bright orange stripe along the top of the body, usually unbroken. The tail displays thick or deep color along the top & bottom. The dorsal fin usually has some color. Both sides of the fish are relatively symmetrical. They are generally larger than grades B & C.
Grade B “Symmetrical”: There is a mid-size / medium black peacock dot on the tail. There is also at least one mid-size / medium black peacock dot on the body. The sides have an orange stripe along the top of the body, which may be broken. The tail displays some color along the top or bottom. The dorsal fin usually has very little if any color. Both sides of the fish are somewhat symmetrical. They are also generally smaller than grade A.
Grade C “Standard”: There is a small size / light black peacock dot on the tail. There are small size / light black peacock dot(s) on the body. The sides have a light orange stripe along the top of the body, which is usually broken. The tail displays very little color along the top or bottom. The dorsal fin usually has no color. Both sides of the fish are usually not symmetrical. They are also generally smaller than grade A.
Endlers are similar to and very closely related to the guppy. In fact, their genetics are so similar that there is debate whether they are officially the same species, a subspecies or simply a breed of guppy. If for no other reason, their own scientific species name of Poecilia wingei is used to signify this difference for conservation purposes.
Broadly speaking, most Endler male colors & patterns are passed along the Y (male) chromosome. This means colors & patterns of male offspring come primarily from the male parent, usually resulting in fathers and sons closely resembling each other. This hereditary process encompasses complicated biological systems, so there are always exceptions. For a more detailed genetic view, check out this Endler / Guppy Genetics Primer.
Additional Endler genetic factoids:
23 pairs of chromosomes, including a pair of gender X & Y chromosomes (coincidentally the same as humans).
Hybridized with the common Guppy (P. reticulata), producing fertile offspring.
Hybridized with Picta livebearers (P. picta) producing offspring with varied fertility rates.
Hybridized with various species of Molly (P. latipinna or velifera) producing offspring that are reported as always males and appear to be infertile.
Observations: N vs P Class
By definition, the difference between N Class Pure Strain and P Class fish should only be documentation; in other words, solid proof that the fish have not been crossbred with "regular" guppies. However, almost every time I’ve come across P Class fish, I have concluded that there has been at least some measure of hybridization. There are several distinct differences when compared to N Class Pure Strain ELBs. These differences include: behavior, color intensity, color patterns, quantity of colors and body shape / morphology. So, although at a glance, the two classes are pretty similar, I'd bet that the vast majority of P Class fish in the real world (every pet store I've encountered Endlers in) have some measure of hybridization. These are the specific differences I’ve noticed when compared to P Class fish:
N Class Pure Strain Males:
Are a bit larger and sleeker.
Display broader variety in colors, color patterns and have deeper color.
Colors have a metallic sheen or iridescent / neon quality (that is hard to capture in pictures). Think glossy vs flat paint.
Dorsal fins seem to be a bit longer.
Tails don’t display unusual shapes (like most modern day guppy tails) and tail “swords” (when present) are not especially elongated.
Interact with each other in more structured ways, like occasionally swimming in sync.
N Class Pure Strain Females:
Are a bit larger and sleeker.
Are less likely to eat fry.
Take more of an interest in males during courtship.
My first impressions of N Class Pure Strain Endlers, after keeping P Class fish for some time, were "These fish seem wild!” There was something I could not quite put my finger on, but the overall impression was definitely distinct and fascinating. Undoubtedly, this impression was a result of all the differences noted above, but which I had not yet outlined. A fitting analogy is the differences we think of when comparing wolves and dogs. In essence, the P Class fish physical and behavioral traits have “softened” or become more dog/puppy like as compared to their wilder N Class Pure Strain cousins.
Of course, it's important to keep N Class fish genetically pure to ensure their continued existence. However, P Class fish are charming in their own right as well. In fact, some of their “dog / puppy" like qualities make them great to fish to keep.
Where do N Class Pure Strain Endlers come from?
Very few, if any descendants of the Endlers collected by Dr. Endler in 1975 remain due to hybridization and inbreeding. However, after speaking with Dr. Endler, a wild fish collector gathered fresh wild Endler stock from their native lagoons in Venezuela. Beginning in the late 1990s and continuing into the next decade, these expeditions collected hundreds of wild Endlers from their native habitat and expanded the captive breeding stock. Although not yet taken up into the IUCN Red List of endangered species, Endlers are either no longer found in the wild or are extremely rare because of habitat destruction and pollution. In essence, Endlers are likely already extinct in the wild, so the stock from these collections encompass the only known N Class Pure Strain population in today’s hobby. In hindsight, the value of these expeditions cannot be overstated since there would not be any Endler populations left in existence without those collections. The stock from these collections was provided to the Endlers Livebearers Association of America (ELAA).
Which fish are considered N Class Pure Strain & how is this documented?
Only fish that are directly descended from the original ELAA stock and which are verified by documentation throughout their entire line of descent are deemed to be N Class Pure Strain fish. This documentation is provided by breeder Registries. My listing in the ELAA N Class Pure Strain Registry (screen captures to the right-highlighted in yellow) validates The Endler Shop’s fish as Pure Strain, by documenting line of descent back to the original stock.
How does The Endler Shop document Pure Strain Fish for customers?
The Endler Shop also maintains an N Class Pure Strain Registry of customers who purchase N Class fish. Since our fish are registered to the original ELAA stock, the listings in our Pure Strain Registry completes the documentation, tracing the entire line of descent back to the original ELAA stock. This validates our customers’ fish pedigree as Pure Strain. Customers with eligible N Class Endler orders (8 fish mixed male & female of a strain) may request inclusion in our Registry during purchase.