Introduction

Through selective breeding, there are many tail types of bettas available today. While veiltail is by far the most common in pet stores, the other tail types such as crowntail and delta are raising in popularity and are now becoming available to the casual betta owner. This article seeks to explain the different tail types and the results of crossing them.



Plakat (PK)

Plakat is used to describe a short-finned tail.  The word plakat(plakad) is Thai for biting fish, and is the tail type of the wild Betta Splendens. Occasionally a plakat male may accidentally be sold as a female betta as there are only subtle differences between them.

Male plakats will have longer fuller ventrals, a pointed anal fin, and a gill membrane or beard. Female veiltails may look very similar, but one can tell the difference by looking at the dorsal fin. Veiltail females will have a knife-like dorsal while a male plakat will have a rounded dorsal. Female plakats may also cause a problem with gender identification. They will have the rounded dorsal fin, but their anal fin will not be pointed, but very trapezoidal. Female plakats also have shorter, thinner ventral fins and no gill membrane.

There are three different plakat tail types around.  The traditional plakat, the show plakat and the symmetrical plakat. 

The traditional plakat will have only 2 branches in his rays, and his tail will have a more rounded look, like the boy I have posted above.  They will have rounded dorsal fins and a pointed anal fin. 

The show plakat will have a rounded dorsal that overlaps with the caudal fin, a pointed anal fin, and its caudal must reach 180*.  This often means they have at least 4 branches on their rays.  

The symmetrical plakat has similar standards to the HM.  The caudal must make 180* spread, and the dorsal must have longer initial rays and the top that touches the caudal must be of the same length.  The anal fin, instead of being pointed like many plakats, will be horizontal and connect evenly with the caudal.

The short-finned tail type is recessive. This means you need plakat genetics from both the male and the female in order to get a plakat.



Veiltail (VT)

Easily the most popular tail type. They were selectively bred from wild betta splendens and introduced to the Western world in 1928. At this time there were plakats, but they were not very popular; it was the long-finned veiltails that took the aquarium hobby by storm.

Veiltails are named so due to their long flowing, drooping fins that resemble a wedding veil. Veiltail caudal fins should arch and droop like a veil, their anal fin should be as long as their tail, and their dorsal long and knife-like. Often veiltails have long, thin ventral fins. This tail type has only 2-ray ray splitting.

The long-finned gene is dominant. If either of the parents are veiltails, they will have veiltail fry. Only if both parents carry a recessive tail type as well will there be anything but veiltails in the spawn.



Roundtail (RT)

As it sounds, a roundtail betta is one with a rounded tail. This is a long-finned variety of betta. Plakats with round tails are considered traditional and closer to the wild type. Roundtail bettas are rather common and often result in delta spawns. As they are often found in delta spawns, they are often sold as deltas.

The genetics for roundtails are not recessive or dominant, but are a naturally occurring variation of the delta tail.



Delta (D) / Super Delta (SD)

Named for the Greek letter Delta, which looks like a triangle, this tail type looks like a triangle. It will have straight caudal(tail fin) edges extending the length of the tail creating clean angles. If the edge rays are not long enough, it will result in a roundtail or something in between. One of the reasons the tail is able to achieve the triangle shape is the increased ray splitting.
In the search for Halfmoons, there are often Super Deltas. Fish that are very nearly Halfmoons, but do not reach the full 180 spread. Super Delta's tails will spread 160 to 179 degrees. Often if a Super Delta is rather close it can be trained to be a halfmoon with regular flaring exercise.

This tail type is dominant over plakat. If crossed with a veiltail, the number of ray splitting will decrease drastically resulting in a spawn that will be predominantly veiltails with an increased caudal spread.



Halfmoon (HM)

Halfmoons are technically just a subset of Delta, like Super Delta is. Halfmoons will have long straight rays, and a 180 degree spread (looks like a "D"). Halfmoons will have multiple ray splitting, from 4 to 16 or even more rays.

Halfmoons are most popular in betta show breeding. Many finnage standards are based on the halfmoon, and for awhile the veiltail was looked down upon as base or common. Lately there has been a surge to bring veiltails to the show popularity that halfmoons currently dominate.

Halfmoons are not dominant or recessive due to the fact that it relies on multiple sets of genes to exist. The best way to get a halfmoon is to breed two very good specimens of halfmoons together and carefully care for the fry. Water conditions can ruin a halfmoon's finnage.



Over Halfmoon (OHM)

This just describes a delta based tail that exceeds the 180 degree spread. Fish have been known to reach spreads greater than 220 degrees.

Over Halfmoons tend to result from halfmoon spawns with more than 4-ray parents. Often OHMs can be used to compensate for a Super Delta parent's short coming.



Rosetail

In the search for more and more ray splitting, the rosetail was developed. This fish has such excessive ray splitting that the edge of its caudal fin will overlap creating a rose-like appearance.

These fish often have birth defects such as "smudged" scales, shorter dorsal and ventral fins, less intense color, and stunted development. It is often discouraged breeding rosetails as they may pass on these genetic mishaps.

Rosetails result from halfmoon spawns with a large amount of branching.

Crowntail (CT)

Crowntails are quite unique looking fish. Crowntails have reduced webbing between their rays resulting in a spiked appearance.

Crowntails can be based on veiltails, plakats, deltas, super deltas, halfmoons and doubletails. Veiltail based crowntails will have long flowing rays that droop like veiltail fins, plakats will have short spikes, and the delta family of crowntails will have the same overall triangular shape.

There are four different types of crowntail ray extensions: Single ray, only one ray extends beyond the webbing edge; Double ray, ray splits into two after the webbing edge; Triple ray, ray splits into three after the webbing edge; and Double Double Ray, each ray splits into two rays which in turn split again into two more rays.

Crowntail is partially dominant. If the fish has two sets of crowntail genes, it will be a crowntail. If the fish is only a carrier of crowntail, it will show as an intermediate tail type called combtail.



Combtail

These are fish that carry the crowntail gene. The will have only slight webbing reduction. A halfmoon combtail is called a half sun.

Doubletail (DT) & variations

Doubletail is actually a genetic fault that results in the bettas tail being split in two. Any of the previously mentioned tail types may be double tail such as a crowntail double tail (CTDT), a halfmoon double tail (HMDT), or a plakat double tail (PKDT).

In addition to having a split tail, these fish have very broad dorsal fins that mirror the anal fin. They also have stouter bodies which makes them more susceptible to swim bladder disorder due to their already shortened swim bladder.

Vary rarely there will be fish with tails split into three lobes, called a tripletail. More often the tail will not split completely into two lobes creating a hearttail.

Doubletail is another partially dominant tail type. A fish carrying doubletail will have a dorsal with a much wider base than normal bettas of their base tailtype. Crossing two doubletails is discouraged as it often results in deformed bodies and bent spines.

Great resources on betta tailtypes:
Betta Territory - Tailtype definitions & genetics
Betty Splendens - Tail Forms & Finnage
Jim Sonnier - Finnage Variations in Bettas