Fin Shape Genetics
Need a basic introduction to genetics? Read this: https://basicbiology.net/micro/genetics/genetic-inheritance
Fin Types - Genetics
I'm going to start off this section by saying that there's even less reliable information on this topic than there is on the color genetics. Some of this may be incorrect. It doesn't help that there are multiple genes interacting each with multiple alleles. I will list the types and dominance of the fin types first, pictures and descriptions will be below. Again, if the second allele doesn't matter, __ will be used to denote this
Plakat
This is the "original" fin shape of the fish, short fins. It is a partially dominant gene, shown as: P__
Veiltail
This is also a partially dominant gene, shown as: V__
Roundtail
This is the result of Plakat and Veiltail genes together, shown as: PV
Delta
This is a dominant gene, I could not find much on it. I think it may be: D__ (It may be dominant over Veiltail and Plakat, as offspring of Delta crosses may contain Roundtails, but it's also said that Halfmoons are a subset of Deltas)
Spadetail
This is a very uncommon tail type, and is recessive (Though dominant over the following, I think), and is shown as: ss
Crowntail
A recessive gene, shown as: cc
Halfmoon
Considered the most recessive gene, shown as: hh
Combtail
The result of Crowntail and Halfmoon genes together, shown as: ch
Could not find any reliable information on:
Doubletails or Rosetails
Plakat
This is the "original" fin shape of the fish, short fins. It is a partially dominant gene, shown as: P__
Veiltail
This is also a partially dominant gene, shown as: V__
Roundtail
This is the result of Plakat and Veiltail genes together, shown as: PV
Delta
This is a dominant gene, I could not find much on it. I think it may be: D__ (It may be dominant over Veiltail and Plakat, as offspring of Delta crosses may contain Roundtails, but it's also said that Halfmoons are a subset of Deltas)
Spadetail
This is a very uncommon tail type, and is recessive (Though dominant over the following, I think), and is shown as: ss
Crowntail
A recessive gene, shown as: cc
Halfmoon
Considered the most recessive gene, shown as: hh
Combtail
The result of Crowntail and Halfmoon genes together, shown as: ch
Could not find any reliable information on:
Doubletails or Rosetails
Fin types - mouse over to see names
Fin Types - Characteristics
The majority of the descriptions for these fin types are coming straight out of International Betta Congress (IBC) Showing manual. The fish pictured above are not ideal specimens, sketches of some can be found in the showing manual link. Names of specific fins can be found in the images above.
Plakat
Plakats are the oldest of the domesticated Betta and are derived from animals bred for fighting. The dorsal and anal fins should not greatly exceed the body width and the caudal fin should not exceed 1/3 of the body length. The dorsal fin may be either uniformly rounded or come to point. The anal fin has a trapezoid shape with the forward (anterior) edge shorter than the rear (posterior) edge. The posterior tip should be pointed. When flaring the rear edge of the anal fin should overlap the lower portion of the caudal fin. The caudal fin may be either spade shaped or rounded. If spade-shaped the point should be at the midpoint of the fin. A caudal spread of 180° is preferred. Ventral fins can be either full or thin, but are expected to be notably longer than in other show Betta, 2/3 the length of the length of the body (as measured from the base of the ventral fin to the caudal peduncle) or longer.
(Show Plakats have different requirements than Traditional Plakats)
Veiltail
The Veiltail is the oldest form of long finned show betta that has no symmetry. The ideal Veiltail has an asymmetrical appearance with a long caudal fin, narrow dorsal and an anal in the form of a trapezoid. The rays in all fins must be evenly curved. The body should be strong and not too skinny
Roundtail
No show standard listed
Roundtails have a rounded caudal fin that does not come to a point. The outer rays are curved, producing the rounded edges.
Delta
No show standard listed
The caudal fin will be triangular in shape, but can be flared to nearly 180 degrees.
Spadetail
No show standard listed
Caudal fins are always in the shape of a spade, which is not to be confused with a veiltail fish. The spadetail will have a long caudal fin that meets at a point and the bottom fins are also straighter and a bit pointier than other bettas.
Crowntail
The supporting webbing around the fin rays is reduced and the rays protrude past the edges of the fin membrane. Ray should be thick and straight. Slightly outwardly curved extensions in caudals with double-rays are desirable to give the “cross-ray” effect. Double Ray – webbing is reduced at two levels; one between a pair of rays and the other (more profoundly) between two branches. 4-ray and 8-ray extensions are less common and the effect is almost always confined to the caudal fin. Single Ray – Web margins are, ideally, uniform and webbing reduction is equal between primary rays and rays with branches. Cross Ray – In the schematic, this is manifested by pairs of primary rays which curve over each other. The caudal should display the splendor of a crown. The caudal rays should display at least double ray extension. A slight gradual curling of the dorsal and anal rays are acceptable but parallel and straight rays are preferred. Ventral fins should display a jagged appearance.
Halfmoon
Caudal Fin should extend to 180 degrees, and when compared with the anal and dorsal fins, should touch and be of equal length (Forming the majority of a circle) See final picture in gallery above for further information.
Combtail
No specific show standards, I believe it is counted as Halfmoon.
The splits between each ray should be drastic enough to be seen from afar. The splits should be at least a third from where it begins all the way to the tip, whereas a Crowntail’s splits are so drastic that it covers the outer half of its fins.
Doubletail
Doubletail Bettas are expected to differ in several ways from the singletail: 1. Possess two distinct “tails” or caudal lobes instead of one, with a complete separation to the base of the caudal peduncle. 2. Possess a wider caudal peduncle to support the double lobes. 3. Possess a larger dorsal fin, nearly the size of the anal fin. 4. Their bodies are usually more “chunky” and often a bit shorter. 5. Bends in the caudal peduncle are expressed to a varying degree in almost all doubletail bettas. These are more easily noticed when viewing the fish from above. Easily seen bends should be faulted; if the bend is not excessive when viewed from above, the fish should not be penalized
Rosetail
No specific show standards.
The Rosetail is an extreme version of the popular Halfmoon Betta. Rosetail describes a type of tailform. Like the halfmoon, the Rosetail has been bread to have a wide 180° spread of the caudal fin. What sets it apart is the increase in the number of branches in the dorsal, caudal and anal fins giving them a ruffled or feathery appearance. When the fins are spread open the dorsal and caudal fins overlap resembling the petals of a rose.
Plakat
Plakats are the oldest of the domesticated Betta and are derived from animals bred for fighting. The dorsal and anal fins should not greatly exceed the body width and the caudal fin should not exceed 1/3 of the body length. The dorsal fin may be either uniformly rounded or come to point. The anal fin has a trapezoid shape with the forward (anterior) edge shorter than the rear (posterior) edge. The posterior tip should be pointed. When flaring the rear edge of the anal fin should overlap the lower portion of the caudal fin. The caudal fin may be either spade shaped or rounded. If spade-shaped the point should be at the midpoint of the fin. A caudal spread of 180° is preferred. Ventral fins can be either full or thin, but are expected to be notably longer than in other show Betta, 2/3 the length of the length of the body (as measured from the base of the ventral fin to the caudal peduncle) or longer.
(Show Plakats have different requirements than Traditional Plakats)
Veiltail
The Veiltail is the oldest form of long finned show betta that has no symmetry. The ideal Veiltail has an asymmetrical appearance with a long caudal fin, narrow dorsal and an anal in the form of a trapezoid. The rays in all fins must be evenly curved. The body should be strong and not too skinny
Roundtail
No show standard listed
Roundtails have a rounded caudal fin that does not come to a point. The outer rays are curved, producing the rounded edges.
Delta
No show standard listed
The caudal fin will be triangular in shape, but can be flared to nearly 180 degrees.
Spadetail
No show standard listed
Caudal fins are always in the shape of a spade, which is not to be confused with a veiltail fish. The spadetail will have a long caudal fin that meets at a point and the bottom fins are also straighter and a bit pointier than other bettas.
Crowntail
The supporting webbing around the fin rays is reduced and the rays protrude past the edges of the fin membrane. Ray should be thick and straight. Slightly outwardly curved extensions in caudals with double-rays are desirable to give the “cross-ray” effect. Double Ray – webbing is reduced at two levels; one between a pair of rays and the other (more profoundly) between two branches. 4-ray and 8-ray extensions are less common and the effect is almost always confined to the caudal fin. Single Ray – Web margins are, ideally, uniform and webbing reduction is equal between primary rays and rays with branches. Cross Ray – In the schematic, this is manifested by pairs of primary rays which curve over each other. The caudal should display the splendor of a crown. The caudal rays should display at least double ray extension. A slight gradual curling of the dorsal and anal rays are acceptable but parallel and straight rays are preferred. Ventral fins should display a jagged appearance.
Halfmoon
Caudal Fin should extend to 180 degrees, and when compared with the anal and dorsal fins, should touch and be of equal length (Forming the majority of a circle) See final picture in gallery above for further information.
Combtail
No specific show standards, I believe it is counted as Halfmoon.
The splits between each ray should be drastic enough to be seen from afar. The splits should be at least a third from where it begins all the way to the tip, whereas a Crowntail’s splits are so drastic that it covers the outer half of its fins.
Doubletail
Doubletail Bettas are expected to differ in several ways from the singletail: 1. Possess two distinct “tails” or caudal lobes instead of one, with a complete separation to the base of the caudal peduncle. 2. Possess a wider caudal peduncle to support the double lobes. 3. Possess a larger dorsal fin, nearly the size of the anal fin. 4. Their bodies are usually more “chunky” and often a bit shorter. 5. Bends in the caudal peduncle are expressed to a varying degree in almost all doubletail bettas. These are more easily noticed when viewing the fish from above. Easily seen bends should be faulted; if the bend is not excessive when viewed from above, the fish should not be penalized
Rosetail
No specific show standards.
The Rosetail is an extreme version of the popular Halfmoon Betta. Rosetail describes a type of tailform. Like the halfmoon, the Rosetail has been bread to have a wide 180° spread of the caudal fin. What sets it apart is the increase in the number of branches in the dorsal, caudal and anal fins giving them a ruffled or feathery appearance. When the fins are spread open the dorsal and caudal fins overlap resembling the petals of a rose.