African tetra... what's the difference...

[Magnum Man]

working with the lighting I have tonight, it's more difficult to see, but on one of my "blood caps" is more transparent than the other... in the right light, one looks like a glass fish, the other is no where near as transparent... thoughts on why... the more transparent is smaller, but I think there is more to it...

 

[Innesfan]

The amount of body cavity occupied by internal organs is often greater for females given that they have ovaries. In transparent fishes, this would make females somewhat less transparent. In this species males also tend to be smaller. I suspect those two factors explain what you are seeing.

 

[Magnum Man]

the clear part seems to be behind the gut mass, in the tail muscle area, and along the back

 

[GaryE]

Which species are you looking at?

Is it the Bathybaethiops breuseghami (moon tetra) or the Phenacogrammus auriantacus? Or both?

 

[Magnum Man]

breuseghami... if you zoom the bottom picture and look at the breuseghami, it looks very "glass fishish"

I've had these quite a while, and I didn't notice that when I 1st got them... they all looked the same

 

[GaryE]

I agree with @Innesfan on that, though to a degree it could be camera angles and backlighting too.

 

[emeraldking]

I also agree with @Innesfan... But there's also another reason. Not all specimens of the same species have the same density of chromatophores (color cells). One with a lesser density will look the same in normal light but once a flash or extra light turns in, the light will go through the specimen with a lesser density of chromatophores, which makes it look translucent.

 

[Innesfan]

Excellent point, @emeraldking. And certainly true of non-transparent and opaque fishes as well.