Unsure what is wrong

Hi one of my X ray tetras is sick, it's struggling to stay in one place, is rapidly moving it's mouth no longer eating and has grey/black patches under the skin definitely not on the outside. Fins look fine too. Every other fish is fine.

Tank size:105l
tank age:2yrs
pH:7
ammonia:0
nitrite:0
nitrate:15
kH:don't know
gH:don't know
tank temp:26c


Volume and Frequency of water changes: 30% weekly


Tank inhabitants: 6 Cardinal Tetra, 8 Harlequin Rasbora, 7 x-ray Tetra, male Betta and some Amano shrimp oh and 2 assassin snails
Sorry pic quality isn't the best he's still really fast.
I've moved him to another tank because wasn't sure if what he has could spread. Not treated yet as didn't want to without knowing what it is.

Any help would be really appreciated.

Could be sporozoan infection.

Not sure whether this would be related or not, but something might have happened between your male betta and your x-ray, because male bettas are not meant to be in a community tank. Even if it's unrelated, I'm pretty sure it's only a matter of time from what I've read on this forum that something happens between your betta and a tank mate. Male bettas are very aggressive.

Thank you Bruce leyland-jones I will read up on that.
Foxgirl158 i will definitely watch him but he's such a softie and gets on fine with the other fish, I think it depends on the temperament of the Betta.

Finseverywhere said:

Thank you Bruce leyland-jones I will read up on that.
Foxgirl158 i will definitely watch him but he's such a softie and gets on fine with the other fish, I think it depends on the temperament of the Betta.

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I got to thinking that, because X-Ray Tetra are transparent, any infestation that would be invisible in opaque fish might not be so in the X-Ray Ts.

Bruce Leyland-Jones said:

I got to thinking that, because X-Ray Tetra are transparent, any infestation that would be invisible in opaque fish might not be so in the X-Ray Ts.

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Doesn't that start with white lumps tho?
Or as you say they are transparent so could be seeing and early infestation? What would be the best thing to treat with do you think?