Glowlight Tetra, Disease. ?

Morning,

I find keeping fish extremely relaxing but also extremely stressful when things aren't going well. This morning I have woken up to find one of my glowlight tetras with a black rash on his face, he/she also looks very bloated. I have attached an image below.......any thoughts or advise on this would be welcome.

Also, Sue I have now taken my Betta out of the tank and it did seem to improve not only his mood but also the general mood of the tank I took him out of.

There is one possible condition that I've read of involving black spots but the symptoms don't seem to be consistent with that unless any more symptoms have developed? Remind us, what fish do you have and when were they added?

Is it the patch of grey skin along the back in the picture?  If it's in the form of spots was your recently added glowlight tetra wild caught?  It could be a sign of flatworms in which case you'd need a treatment with praziquantel.  If you see clamped fins, depression, or breathing problems it could be some form of ectoparasite.  All of these are covered by the relatively mild treatment of Seachem ParaGuard which could be done precautionary.  (I like to use it as part of normal quarantine).

The bloating is weird though as it doesn't fit any of the above.  If your fish doesn't have any of the additional symptoms above it could be that he just got caught somewhere and scrapped off some scales in which case it'll just heal with a little bit of time.