opaque vs pastel

Opaque vs Pastel Betta: What’s the Difference

The subject of betta genetics is fascinating and can sometimes be very confusing for the newcomer to the fascinating world of breeding these beautiful fish.

In this article, we take a look at two of the most popular betta variants, the opaque and the pastel betta, to give you a greater understanding of the genetics behind these two strains.

First of all, let’s explain the genetic makeup of an opaque white betta:

Genetic Makeup

The genetic makeup of the opaque white betta is: C Bl Si Nr Op

C = Cambodian gene for lack of dark body pigment

Bl = Steel blue pigmentation that presents as silver-white when on a light background

Si = Gives a spread of iridocyte pigment, i.e., steel blue over the whole fish

Nr = Non-red, meaning that the fish cannot produce red pigment

Op = the Opaque gene that causes opacity or powdery appearance of the fish

In this case, Si is regarded as dominant. C and Nr are treated as recessive, and Op is regarded as partially dominant – one allele for opacity is visible, but two alleles are highly visible. 

Op is the gene that is characteristic of opaque betta fish. 

What is an Opaque Betta?

In the world of betta fish breeding, opaque does not solely mean white. In fact, there are three forms of opaque:

  • Blue (royal blue)
  • Steel blue
  • Green

However, frequently when people refer to opaque white bettas, what they are actually talking about is steel blue opaque fish. However, thanks to the appearance of the fish, the term “opaque white” is generally used. 

Also, there are other forms of opaques, including blue and green opaque bettas. Blue and green opaques have a blue or green sheen, rather than pure white coloration. In all cases, the term “opaque” refers to a fish that possess the Op gene only.

So, you can see that if you crossbreed a blue opaque with another blue opaque, the spawn will contain green, steel, and blue opaques. Similarly, if you crossbreed a blue opaque with a steel opaque, you will get blue and steel opaques (i.e., opaque white).

An opaque white betta will take the light body color from the Cambodian (C) genes. However, it is also known for opaques to be created as a result of using fish carrying marble genes. For that to happen, the steel iridescence and the opaque factor must both be present.

In an opaque, the opaque (Op) factor must be present in at least one of the parents. Ideally, both of the parent bettas would be some form of blue, i.e., steel blue x royal blue or steel blue x steel blue), which would produce some steel progeny. Both of the parent bettas would need to be marble genos.

Problems with Opaque Bettas

Opaque betta fish have a number of inherent problems. As the fish is white, any tiny color defect, such as black lips, black scales, etc., stands out a mile against the glowing, pristine white of the fish. 

Also, unfortunately, white pigment doesn’t blend too well with the underlying yellow color on the fish’s body. That often results in a distinctly yellow wash. Some strains are predisposed to having a slightly bluish tinge, especially on their fins.

Another common issue with opaque white bettas is their poor quality finnage. To obtain that pristine, pure white coloration, breeders tend to choose bettas for their color quality, rather than their finnage. As a result, the finnage of most opaque white bettas that are generally available in fish stores does not compare well with the finnage of many of the other color strains.

However, on the plus side, opaques do tend to be a little less aggressive than some of the colored strains of betta fish, although there is no clear genetic reason for that.

The International Betta Congress (IBC) standard defines opaques as:

Non-red, light-bodied fish similar in appearance to pastels. However, there are guanine deposits, giving a denser, milkier, appearance, and opacity to the coloration of these fish.

These deposits are most visible around the head and eye and continue to accumulate as the betta ages.

As previously mentioned, opaque bettas and pastel strains are often confused. So, now let’s find out more about the pastel betta.

What is a Pastel Betta?

The genetic makeup of a pastel betta is: C Bl Si Nr, which is identical to that of the opaque betta, so:

C = Cambodian gene for lack of dark body pigment

Bl = Steel blue pigmentation that presents as silver-white when on a light background

Si = Gives a spread of iridocyte pigment, i.e., steel blue over the whole fish

Nr = Non-red, meaning that the fish cannot produce red pigment

Op = the Opaque gene that causes opacity or powdery appearance of the fish.

However, in pastel bettas, the opaque gene is optional, although it is necessary to some extent. If too little opaque factor is present, the fish will have a translucent appearance. If too much opacity is present, the IBC may classify the betta as opaque.

Pastel bettas are iridescent (steel blue, blue, and green). It is the non-red or Cambodian gene that differentiates the pastel from the regular dark-bodied iridescent bettas. Pastel bettas are homozygous for Cambodian, and it’s that that gives them the light flesh-colored body.

Most pastel bettas carry a small quantity of opaque factor that makes the iridescence appear more solid. If the opaque factor is lacking, the iridescent color will present as translucent in the absence of black or red (dark) pigment.

So, it is actually true to say that opaque bettas are also pastels, except that opaque fish carry much more of the opaque factor than pastel bettas do. Therefore, by crossing an opaque with a pastel betta, the progeny would all be pastels. 

A good quality pastel betta must have a light quantity of opaque factor, and such a crossbreeding will increase the quantity of an opaque factor along the line.

So, what’s the difference between an opaque and a pastel betta?

If you’re looking at a white betta fish in your local fish store, how can you tell if it’s a pastel or an opaque?

Well, the key to distinguishing an opaque betta from a pastel is the thick powdery “white” pigmentation that is present. The easiest way that you can see that feature is by looking down at the fish from above and studying the area around the fish’s head. 

In an opaque betta, the dense pigment extends all along the fish up to and including the nose. In pastels, the pigment typically doesn’t reach as far up or, if it is present, is usually very sparse.

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