Pin tail, veil tail, flag tail… – learn about guppy standards
The guppy (Poecilia reticulata), a widely esteemed aquarium fish, has captivated the fascination of aquarium enthusiasts worldwide. Its popularity stems from sought-after attributes such as size, body colors, and fin shapes, all of which are key considerations for aquarists. It is the fin shapes, particularly, that warrant special attention when describing guppy standards.
What are guppy standards?
These standards are just patterns of shapes, sizes and proportions of fins (mainly caudal and dorsal) in relation to the body of males. They were developed by breeders who, through years of careful observation, discerned distinctive tendencies in the individuals they bred, directing the development of their fins toward specific orientations. Together they described the first patterns of guppy standards, refining them with years to come.
Of course, it is not mandatory to have guppies with only standard shapes, but breeding specific standards and selecting them based on patterns allows you to enjoy the beauty of the highest quality. In addition, it provides a basis for comparing the results of breeding work and a chance to participate in competitions and exhibitions of these unique fish.
Anyone who has ever owned guppies will admit that, more than once, when looking at individuals, they have tried to spot unique characteristics in them. It didn’t matter whether it was a newly acquired individual or adolescent fry. It was always thrilling to observe those and wonder if they will have large fins or small fins; a round tail or a triangular one, or it will grow swordtails.
That’s how the first work on creating patterns of standard guppy fin shapes began. As a result of these efforts, 13 guppy standards recognized in the Internationales Kuratorium Guppy Hochzucht (IKGH) organization have been developed. A description of which can be found in the Internationalen Hochzuht Standards (IHS) document. The first version of the IHS was created in 1981, and since then (do for more than forty years) it has been systematically revised and adapted to the current knowledge and health-promoting requirements of the guppy.
Classification of guppies should begin with the applicable division into three groups (broad tails, sword tails and short tails), in which each standard is placed.
Broad Tails
This group includes 5 standards, having the largest and most impressive tail fins.
Fan Tail
The tail fin, as the name suggests, resembles a fan. It has the shape of an elongated triangle with a length equal to the length of the body. The dorsal fin initially rises upward, then runs parallel along the body, tapering gradually and ending sharply at 1/3 of the tail length.
The fan, although somewhat similar to the triangle, is clearly distinguished from it by the length and width of the caudal fin, as well as the shape of the dorsal fin. It is encountered at competitions and exhibitions, but it is not the standard shown in large numbers. In the trade, it is confused with the triangle.
Triangle Tail
The caudal fin is shaped like an equal triangle with a dimension of 8/10 of the body length. The dorsal fin initially grows upward, then turns backward, reaching up to 1/3 the length of the caudal fin. It is wide but even. It looks like a rectangle.
A decent triangle, despite its large fins, should swim gracefully. This is the most popular guppy standard shown at competitions and exhibitions, but it is also the most popularly bred by breeders and purchased by aquarium store customers.
Vail tail
The caudal fin has an outwardly arched edge and is topped with a concave rim. The length is 8/10 of the body length. The dorsal fin rises vertically, then runs along the body, reaching up to 1/3 the length of the caudal fin. It is finished in a circle.
This is a guppy standard that is rarely presented at competitions and exhibitions. It is unlikely to be found in aquarium stores, and if it is, it is mistaken for the triangle, just like the fan tail.
Flag Tail
The caudal fin of this standard is shaped like a long rectangle and resembles a flag. The length should be 8/10, and the width should be 4/10 of the body length. It ends straight. The dorsal fin, like that of a veil tail, initially rises upward, then runs parallel along the body, tapering gradually and ending sharply at 1/3 the length of the tail.
Flag tail is another sparsely presented standard of guppies from the broadtail group. While having an undoubtedly interesting shape, it is rarely seen in the trade.
Half Moon tail
The caudal fin forms a semicircular shape, with vertically aligned edges. Its length should be 2/3, and its height should be 4/3 of the body length. The dorsal fin rises steeply, but not vertically. It has a quarter circle shape and reaches 1/4 the length of the caudal fin.
Half Moon is the youngest standard described and approved at IHS. It is increasingly popular at exhibitions and competitions. In aquarium stores you can often find individuals of the Half Moon standard type coming from batches of fish imported from Asia, but – happily – more and more often from domestic breeding.
Sword tails
This group includes 4 standards, having tail fins with clearly distinguishable sword-like forms.
Double Sword Tail
The caudal fin in its structure has two extensions of the upper and lower rays forming a sword-like form. The middle part is short, rounded and clearly separates the swords from each other. The total length of the caudal fin is equal to the length of the body. The opening of the swords forms an angle of 30°. The dorsal fin initially rises upward, then runs parallel along the body, tapering gradually and ending sharply at 1/3 of the tail length.
Double sword tail is the most popular standard among swordtail guppies. At exhibitions and competitions, it often accounts for more than half of the presented sets from this group. It is equally popular in trade.
Top Sword Tail
The caudal fin of the upper sword, as the name suggests, is formed from a sword-shaped appendage made of extended upper rays. Its length should be equal to the length of the body. The base of the fin is rounded. The sword can be parallel, as well as raised slightly upward to a maximum of 15° relative to the body axis. The dorsal fin, like that of the double sword tail, initially rises upward, then runs parallel along the body, tapering gradually and ending sharply at 1/3 the length of the tail.
The popularity of upper swords at guppy competitions and exhibitions is not the greatest. However, there is no guppy show event that lacks upper swords. You can also buy representatives of this standard in stores or aquarium exchanges.
Bottom Sword Tail
The caudal fin, like in the upper sword, is rounded at the base, except that it has an appendage that forms a sword from the lower rays. The base of the caudal fin is rounded, and its total length is equal to the length of the body. The sword should be angled downward, forming an angle of 15° to the body axis. The dorsal fin, as in the double sword tail and upper sword tail, rises upward and then runs parallel along the body, tapering gradually and ending sharply at 1/3 the length of the tail.
The lower sword, like the upper sword, is a constant, albeit sparsely presented standard at competitions and exhibitions. It can also be purchased in aquarium stores, although rarely.
Lyre Tail
The shape of the tail fin resembles a lyre. The base of the fin is rounded, but broader than that of the double sword tail. It creates a clear gap between the appendages. Similarly to the double sword tail, the lyre also grows the aforementioned two sword-like outgrowths, except that they initially grow horizontally, then move away from each other with length, deviating slightly outward and reaching a maximum of 8/10 of the body length. The dorsal fin, as in other swordfish standards, initially rises upward, then runs initially parallel along the body, gradually tapering and rising upward, ending sharply at 1/3 of the tail length.
Lyre is the least popular swordtail guppy standard both at competitions, shows and in trade. It is often confused with the double sword tail, although it is clearly different, if properly selected for breeding.
Short tails
This group includes 4 standards, having tail fins that are noticeably smaller than in previous standards.
Spade Tail
The first representative of the group of shorttail guppy standards is the spade tail. The name comes from the shape of the tail fin, which resembles the popular trenching spade. Its length reaches half, and its width 8/10 of the body length. The top and bottom edges are straight, running parallel. The tip of the fin descends evenly from the end of the edges to the body axis, forming a fine tip. The overall appearance can also be compared to a hexagon. The dorsal fin initially rises upward, then runs parallel along the body, tapering gradually and ending sharply at 1/3 of the tail length.
The spade tail, once more popular, is now being shown less and less frequently at guppy competitions and exhibitions. Commercially, you can often find representatives of this standard, but they are far from perfect, often being random individuals in a group of other guppies in the tank.
Spear Tail
The tail fin is shaped like a spear. But in other languages they tend to call it a flame. The initially expanding fin reaches a width of 6/10 of the body’s length, then gradually narrows, forming an apex in the axis of the body and reaching 8/10 of its length. The dorsal fin, like that of the standard lyre, initially rises upward, then runs initially parallel along the body, tapering gradually, rising upward and ending sharply at 1/3 of the tail length.
The popularity of spades at competitions and exhibitions is not high, but they are practically regulars at these events. Commercially, their popularity is modest, but they can be found in stores.
Round tail
The tail fin is round, shaped like a table tennis racket, that’s why it is called “racket” in some languages. The length and width should be half the length of the body. The dorsal fin is modest, initially erect reaches its length to the base of the caudal fin. It is rounded at the end.
At competitions and exhibitions, the round tail is the most widely exhibited standard among shorhtail guppies. They are also popular in the trade, and can be easily purchased. Although the fins are smaller than those of, for example, a triangle, a flock of guppy standard round tails swimming very vigorously can make a big impression.
Needle / Pin Tail
The caudal fin of the pin tail is initially circular and reaches a diameter of 4/10 of its total length. At its end, it grows along the axis of the body and runs horizontally, forming a pin – a long, narrow outgrowth formed by two or three rays. The total length of the caudal fin is equal to the length of the body. The dorsal fin initially rises upward, then runs parallel along the body, tapering gradually and ending sharply at 1/3 of the tail length.
The pin tail is an increasingly rare standard at guppy shows and competitions. Increasingly, only a few sets are shown, and often none at all. The situation is no different in commerce, where it is rarely seen.
How are guppy standards evaluated?
In describing the various standards, I used a general description of their characteristics. During competition, individual features of their structure and appearance are considered in great detail. The following tables show the scoring of the competition set in the pairs competition according to IHS regulations:
| Male | Size | Shape | Color | Total | |
| Body | 8 | 8 | 12 | 28 | |
| Dorsal fin | 5 | 8 | 10 | 23 | |
| Caudal fin | 10 | 20 | 14 | 44 | |
| Vitality | 5 | ||||
| Total | 100 | ||||
As can be seen from the tables (the highest number of points), the most important in the evaluation are the shape and size, that is, the proportions of the fins and body. Color is equally valuable, and thus its saturation and evenness. Health, which is judged by looking at the behavior of the fish, and how they are matched to one another to each other, are also important.
| Female | Total |
| Size | 3 |
| Shape | 3 |
| Matching | 2 |
| Vitality | 2 |
| Total | 10 |
Any defect that causes deviations from the described guppy standard results in a reduction in the number of points awarded, i.e. a reduction in the final rating of the set.
The guppy standards outlined above, while generally accepted, are not a closed list and there is still room for expansion. An example of such a situation is the Half Moon guppy standard, was approved and described in the IHS only in 2018.
Guppy standards not yet approved at IHS
Three more proposals are in the queue to be developed into descriptions and approved as standards at IHS. Although these standards are rarely shown in competitions and exhibitions held under the auspices of the IKGH, they are widely recognized and judged in World Guppy Contest competitions. Perhaps they too will join the set of guppy standards described in the IHS in the future.
They include: Longfin ribbon, Longfin swallow, Crown tail.
Longfin Ribbon
The name refers to the long anal and ventral fins, which somewhat resemble the ribbons. In males of this variety, the reproductive organ formed from the transformed anal fin (the gonopodium) is highly elongated. Such a structure means that it cannot perform its primary reproductive function and is only an ornament. Males with a normally built gonopodium are required for reproduction. The caudal fin and dorsal fin are those of the triangle standard. The caudal fin is shaped like an equal triangle with a dimension of 8/10 of the body length. The dorsal fin initially grows upward, then turns backward, reaching up to 1/3 the length of the caudal fin. It is wide but even. It looks like a rectangle.
Longfin Swallow
The name refers to the long, somewhat swallowtail-like stripes made up of joined rays that form the caudal fin. In addition, it is triangular, but rounded outward at the end, reaching a size of 8/10 of the body length. The anal fin and ventral fins are elongated as in Longfin ribbon. In males of this standard, the reproductive organ formed from the transformed anal fin (the gonopodium) is highly elongated. Such a structure means that it cannot perform its primary reproductive function and is only an ornament. Males with a normally built gonopodium are required for reproduction. The dorsal sail fin initially grows upward, then gently turns backward. It ends with a small spike. It is wide, reaching to the base of the caudal fin.
Crown Tail
The name refers to the long, single, unbranched and unconnected rays that form the caudal fin and dorsal fin. The caudal fin is triangular, but rounded outward at the end, reaching a size of 8/10 of the body length. The dorsal fin initially grows upward, then turns backward. It reaches to the base of the caudal fin.
Guppy standards vs. breeding work
As we all know, unfortunately nothing is perfect. There are many objections to the classification and evaluation of guppy standards, which causes them to be developed and improved all the time. Despite the development of descriptions, there always remains the possibility of the breeder’s own interpretation of the standards. On the other hand, the standard does not come from unfounded notions and fanciful forms.
On the contrary, it is based on the developmental tendencies of the guppy and indicates the direction in which the breeders should conduct their breeding work to be able to achieve maximum beauty from their strain. Using these studies, each breeder has a tool to work on his guppies, and having common breeding goals, he or she can compare the results of their work with other breeders. Without a description of the standards, each breeder would carry out breeding work solely according to their own taste, and it would be very difficult to compare the results of these activities.
A few words from the breeder
In conclusion, I would like to add that the most important thing in breeding guppies is to fulfill dreams. From the small ones like getting your first fish fry or buying a dream pair of fish in the store to the serious ones like winning the title of European or World Champion for Guppy Breeders. One of my dreams was to breed my own lines of oin and lyre guppy standards. After many years of patient work, thanks to the valuable advice and help of colleagues, I managed to obtain and refine patterns that were unique for me. Of course, they are not perfect individuals compared to the benchmark, but this gives me motivation to continue working on them. I encourage everyone interested in breeding these beautiful fish to expand their own knowledge about them and to start working on their own dream guppy standard.
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Mariusz Sobierajski
Vice president of Poecilia Reticulata Club
