Boesemani rainbowfish: only one side of head has turned black

[Aanand]

Hello Everyone,
Hope everyones' and their family are in good health.
I have 5 Boesemani rainbowfishes since the last 2 months.
Other tank mates are severums, denison barbs, silver dollars.
Since yesterday, one of the rainbow fish's head has turned black. That too, only one side of the head. The fish is swimming fine.
All the other fishes are fine too...
Unable to find reason why?
Thanks.

 

[MrsE88]

How strange. Any signs of damage to that side of the face?
the only time I’ve really noticed fish get black marks is when they are healing from an injury.

 

[Magnus_Bane]

Personally I think it's just coloring up. It looks like it's getting is adult colors atleast. I'll post a pic of a mature one I got from Google.

 

[MrsE88]

Personally I think it's just coloring up. It looks like it's getting is adult colors atleast. I'll post a pic of a mature one I got from Google.

View attachment 1410500

But have you ever seen them get dark like that on just one side of their face? It still seems like there is a different reason behind ops fish turning dark like that.

 

[Magnus_Bane]

But have you ever seen them get dark like that on just one side of their face? It still seems like there is a different reason behind ops fish turning dark like that.

Very possible, could also possibly be a mutation as well. It could even be a accidental hybrid to. Personally I never own that specific specie before, I've only ever had Australians and an albino millennium red.

The OP should test their water parameters and post the results to rule out any underlining causes. Personally I'm still leaning towards the maturation process but I could easily be wrong too.

 

[Aanand]

How strange. Any signs of damage to that side of the face?
the only time I’ve really noticed fish get black marks is when they are healing from an injury.

No damage. If you look closely, it looks like someone has painted the black colour..

 

[Aanand]

Personally I think it's just coloring up. It looks like it's getting is adult colors atleast. I'll post a pic of a mature one I got from Google.

View attachment 1410500

This ines 2.5" - 3"..

 

[Magnus_Bane]

This ines 2.5" - 3"..

So it could very easily be getting it's adult colors then. I'd still post the water parameters to rule out any other possible causes.

 

[Aanand]

Very possible, could also possibly be a mutation as well. It could even be a accidental hybrid to. Personally I never own that specific specie before, I've only ever had Australians and an albino millennium red.

The OP should test their water parameters and post the results to rule out any underlining causes. Personally I'm still leaning towards the maturation process but I could easily be wrong too.

Water seems fine. I never check parameters though.
Other fishes including the other rainbows are perfect. They are eating well. Good appetite.
I do weekly water change. Add a bit of rock salt and black water after the water change.
Have been doing this for a long time without any casualties.

 

[esoxlucius]

I have boosemani rainbows, males and females. The males can switch their colours on at will and can be quite stunning. The darkest mine have ever gone is deep cobalt blue at the front and deep orange yellow at the rear, very much like the pictures above. And during intense courtship behavior, as well as the deep blue and orange, they also have a white stripe running from the dorsal fin right down to the tip of their snout.

I must say though none of mine have ever gone black and it's even more peculiar that it is only on one side of the head! Very strange.

All I can suggest is to keep an eye on it.