Difference between Opaque & Pastel

I’ve seen this question popping up again and again in most bettas’ forums, and let me compiled the answers from all over the net and share it with you.

The genetic make up of Opaque White is C Bl Si Nr Op.

C – Cambodian gene for lack of dark body pigment

Bl – Steel blue pigment which appears silvery-white when o­n a light background

Si – The spread of the iridocyte pigment, in this case steel blue over the fish

Nr – Non-red, i.e. the inability of the fish t o produce red pigment

Op – Opaque, the special gene that cause the opaqueness or powdery appearence of the fish

“Si” is treated as dominant, “c” and “nr” are treated as recessive, and “Op” as partial dominant. Opaque is partially dominant – a single allele for the trait will be visible, but 2 alleles will be very visible.

Op is the gene that characterises Opaques.

Opaque does not mean White. There are 3 types of Opaques: Steel Blue, Green and Blue (Royal Blue) Opaques. But very often, when we say Opaque White, we are referring to Steel Blue Opaque bettas. However, because of the appearance of the betta, the “Opaque White” term is used generally.

There are also other opaques like Green and Blue Opaque bettas. Green and Blue Opaques have a Green or Blue sheen instead of pure white colour. Opaque refers to the fish possessing the “Op” gene o­nly.

Therefore, if you cross Blue Opaque x Blue Opaque;

You will get Blue, Green and Steel Opaques.

And If you cross Blue Opaque x Steel Opaque;
You will get Blue and Steel Opaques.
(Steel Opaque means Opaque White)

Opaque White get the light body from (C) cambodian genes, but it is also possible for opaques to arise as a result of marble genes. In order for that to happen, the steel iridescence and the opaque factor must be present.

The (Op) opaque factor must be present in at least in o­ne of the parents. Ideally both the parents would be some sort of Blue (Steel Blue x Steel Blue or Steel Blue x Royal Blue), in order for some of the progeny to be Steel. Both would have to be marble genos.

Opaques have inherent problems. Any small color defect, a black scale, black lips etc., will stand out very noticeably against the white betta. The white pigment does not blend well with the underlying yellow bodies too. This may results in a distinct yellow wash. Other strains may seem to tend towards having a blue tinge, especially o­n the fins.

Another problem with opaque white is the poor quality finnage. In order to have pure white, breeders of opaque white tend to select bettas for colour quality instead of finnage. As a result, our current stock of opaque white do not compare well in finnge to other colour strains.

One good point of opaques is that they are a little less aggressive than other strains.

The I.B.C. judging standards define this breed (Opaques) as: Non-Red light bodied fish similiar in appearance to Pastels. However, there are guanine deposits giving a denser milkier appearance and an 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.

To distinguish an Opaque betta and a Pastel, the thick powdery “white” pigment is the key. This can most easily be observed by looking at the fish from above and around the head. In an Opaque, the dense pigment goes all the way up to and including the nose, while in Pastels the pigment usually does not reach as far up or if present is usually sparse.

The genetic make up of Pastel is C Bl Si Nr.

C – Cambodian gene for lack of dark body pigment

Bl – Steel blue pigment which appears silvery-white when o­n a light background

Si – The spread of the iridocyte pigment, in this case steel blue over the fish

Nr – Non-red, i.e. the inability of the fish to produce red pigment

Op – Opaque, optional but necessary to a degree. If too littely opaque factor, the fish appear translucent, and if too much, they may be classified as Opaques.

Pastels are iridescent bettas (Blue, Steel Blue and Green). It is the (C) Cambodian or Non-Red gene that differentiates them from the regular dark body iridescent bettas. Pastels are homozygous for Cambodian, which gives them the light flesh coloured body. Most Pastels also carry a little Opaque factor to give the iridescent appear more solid. Without the Opaque factor, the iridescent color would be translucent in the absence of dark pigment (black or red).

You are right to say that Opaques are also Pastels, except that Opaques carried much more Opaque factor than Pastels. Therefore, if you cross Opaque x Pastel, it will give you Pastels as well. A good pastel must have a light dose of Opaque factor, and such a cross will increase the amount of Opaque factor along the line.

* Compliments to Sean, Kevin, Steve and Gene Lucas. Please learn with open mind, nothing is absolute. I would also like to thank those who have shared their experiences and knowledge with me.

Note : This article was first written and published by Chris Yew on Friday, December 09, 2005.