When it comes to green bettas, there are a few specific types of green color that are possible with Siamese fighting fish. The reason for this is that all bettas can be either metallic or opaque depending on the genetics involved, and the metallic varieties can have green colors that are very dark, light, or even a greenish-blue. Also, bettas can have a multicolor trait that has green or blue mixed with colors like red or yellow!

We will start by discussing opaque green bettas since they are the simplest to understand. Opaques have no dark under-color. They should have very dense and bright color that is primarily one hue (instead of having both green and red, for example). There should be no shimmer to the scales or fins. If you were showing an opaque green Siamese fighting fish at a fish show, it would ideally have a pastel green color! These fish are quite attractive and sought after by many breeders and pet owners alike.

Metallic green bettas, however, are quite a bit trickier to describe. The genetics of metallic green fish involves dominant and recessive traits. The gene for green is denoted as "Bl" and is dominant to the blue gene (which is called "bl"). All fish have two copies of any given gene and bettas with two of the dominant form of green will be a true green. If a betta has one dominant and one recessive green gene, they will be royal blue, and if the have both recessive copies the fish will be steel blue in color.

With the metallic green bettas, the amount of green color will also be determined by another genetic factor for something fish keepers call 'spread iridescence'. This gene can cause the color to appear more of a turquoise hue. It also determines if the fins or the whole body have the green color.

Finally, the hue of green that is preferred is a dark, almost hunter or forest green. This is produced when the black layer of pigment in Siamese fighting fish is thick enough to show through the green. Fish with more black will have a darker, more pronounced color of green in their scales and fins. Unfortunately, this type of green is very rare and difficult to breed well. For this reason, these fish are typically bought up quickly and a hefty price is charged.

As you can see, the genetics that make up the color that bettas develop can be quite confusing. If you even remotely care about the genetics involved, then you are likely considering breeding some of these fish. If that is the case, it is worth spending more time researching the genes that factor in when breeding green bettas.