It has being a long time I wanted to write on this. Apparently, it's something that most halfmoon breeders will encounter, but discussion on such type of bettas isn't much and detailed analysis virtually does not exist in any betta literatures.

The terminology "mutant" is coined as rather unofficially. Some may refer them as "runts ". Perhaps it is time we give a meaningful standard terminology to such fishes.

One thing we can't possible miss them out when we are trying to jar our potential fries. Their fantastic finage! They have wonderful traits, in term finage,something that we all are looking for in our halfmoons. 1) Perfect straight edges and 2) Multiple rays branching. However, the situation may not as rosy as we thought. Once these fellows grow older, they will have rapid breathing, hanging on the water surface gasping for air. Also they will fall sick more easily as compared to their "normal" siblings. However it seems to me that mutant females will be healthier than the mutants male. It is just my personal hypothesis, not based on any scientific controlled experiments.

Where did mutants come from? Are they congenital defects or due to inheritance?

Again, no scientific studies have revealed much answer for this. Some said too much inbreeding will give you mutants. But I'm pretty sure this is not true. I have done many F1 spawns from different sources and in the first generation, mutants fries have already appeared. Quoting from Peter Goettner "A red male from Thailand and a red female from Rajiv. 50% of the offspring were mutants and I did not get any halfmoons. " Even when both parents are not mutants, mutants will still appear. From my experience, mutants are more likely to appear when the parent's siblings are mutants. I have a friend who has tried a mutant pairing spawn and have only 4 fries. All are mutants. The spawn size may be too small to conclude anything but it seems to me that mutants traits may due to inheritance. I will leave this issue till here and hopefully someone will to be able to tell us more about it.

Are mutants good or bad?

It is very subjective issue here. But personally, it means more bad than good. Bringing them to adulthood is a challenge. However, I have seen some Thai's mutants betta able to reach full adult size. Is it the water or the food? I don't know. But for sure, given a good diet and excellent living conditions, they are not that likely to fall sick and will reach their adulthood faster. There are two school of thoughts.1) when u get mutants in your spawn, there will be HMs. 2) when u get mutants in your spawn, there will NOT be HMs. I shared the same sentiments as Peter Goettner. I realized that when I have mutants in my spawn, I can't expect too much quality fishes. However, it seems to me the former hypothesis may also be true, but more for the solid irids colors.

Are mutants able to spawn?

Yes! Of course they can. But the question is: Are they easier to spawn than the normal ones? Are they able to produce fishes of better quality in their progenies? I need more spawning experiences to provide a good answer for this. Mutants are harder to spawn. That's obvious to me. Mutants male build lousy nest or even can't! Too weak to do a proper embrace even when the female is ready to mate. Egg eaters! Agony.Agony.Agony! Mutant females are less readily to mate, but it most cases, given proper conditioning, it isn't a big problem. Oh yes, mutants females have fierce eyes like males. I wonder if that's the reason why my male wanted to fight with them instead of courting. Below is a picture to show the eyes of a red mutant female.

Different degree of "Mutant-ness" in mutant's betta?

I have mutants who already display symptoms swim bladder disease at as young as less than 1 month. Some already start hanging on the surface before they are old enough to feed on bloodworms. But I also have mutants that are still healthy till three months, have thicker bodies than those from weaker spawns. Definitely it is not so simple. A mutant may have some sort of degree in their "mutant-ness". The degree of defects may not be so great that they may turn up to become adults and be fathers of various spawns. Will their progenies be better or worse? I'll leave this for you to find out.

Lighter bodies?

Mutants usually appear to be light bodies or lighter bodies. What do I mean by this? If a spawn is going to throw u some light bodies fries and some dark bodies fries. I will be seeing more mutants in light bodies. The dark bodies seem to be normal and healthy. If a spawn is going to throw to all dark bodies like turquoise X turquoise, the mutants turquoise usually have lighter bodies. Lacking in sufficient melanin or Cambodian genes? I will be more than grateful if any scientist is able to tell me the why? In term of colouration, a light turquoise betta doesn't seem too appealing.

Skinny bodies?

Mutants are easily identified by their skinny body (and perhaps some says thinner scales). The body seems too weak to hold their caudal fins as the caudal fins grows longer and longer. It becomes really ugly to have your fish showing you a very awkward and ungraceful position as it flares. Below is an adult mutant Cambodian to illustrate my point.

Should I be using mutants to breed?

There is no right and wrong answer. If you think you are going to produce a better spawn in the next generation, by all means go ahead. That's nothing to stops you. Even though it seems I have heavily condemned mutants for their negative traits, their finage are still something positive we are looking for in our HMs. Here, we need more people to share with us their knowledge and experience. More people to carry out analysis to understand them. To deem them as useless bunch of genetically weak fishes or treasure them as the key of getting good HMs? Will introducing plakat or wild types bloodline into these fishes give us healthier HMs of stronger bodies in the future generation? Will altering water conditions like ph level or water hardness remedy their rapid breathing difficulties? The mystery will never be unveiled unless we attempt to address these issues.

I'll update again as soon as I discover something new I can write about.