Hi all, new here and hoping you can help.
I've lost all my guppies to whatever disease this is. They get a pale discoloration usually under the dorsal fin although a few of my fry got it around the head before they died. Once the discoloration shows they last 3-4 days. Started off when I added a couple of new guppies - quarantined for a week but obviously not long enough because even though they had no symptoms it started right after.
In the later stages the adults rest on the bottom just balancing with their tail. They die about a day after they do that.
It isn't on the surface of the scales, it is discoloration just underneath like as if the muscle tissue is changing colour or there is a tumour/cyst.
On this female you can see the discoloration through her body, and you can see her spinal cord so it isn't on the surface it is inside the body. I tried to get a pic of the far side but she is keeping away from the camera now so all I can say is it looks the exact same except there is a slight bulge above where the paleness is.
The closest thing I can find to it is false neon tetra disease, am I right? I do have neon tetras but they do not share the symptoms and the guppies have lived with them for a long time without symptoms.
Another thing is that no other fish are getting the disease, it is limited to the guppies.
Any ideas, or advice on what to do to try save my last 3 guppies? 2 are showing symptoms :(