Sick Neon Tetra

Hi,

Very concerned about one of my neon tetras. I discovered today that it has what can only be described as a broken back? It's back end is bent out if shape almost like the letter U. It also had lost most of its colour at it's back end.

Can someone please help?

Do you see any parasites or things that are out of the ordinary other than that? Do any other fish show anything that could be similar or change into that? 

No nothing obvious other than a small white spot on its side.
Photo attached

Hhhmmm, well the white spot doesn't sound good. Does it use its tail? What are its tank mates? Tank size?

It's not swimming freely, it's in with other neons, harlequins and a dwarf goueami

Have you tested your water? looking at the stones under the neon you may have blue-green algae which is a cyanobacteria which from research information it can be very harmful to fish. Unfortunately I have never had to treat it myself so cannot offer any help there, maybe if you do a post in the algae removal section someone can help and confirm that is is blue green algae for you and the best way to remove it.
 
In the meantime for the neon if possible I would remove it to another tank and treat it with an antibacterial medication,