Sick Neon Tetra

[caino]

Hey i have got a sick neon tetra on my hands i think, it is my friends and iv got a spare tank to quarentine it im not sure what his water speks are but mine are all fine it has a sponge filter thats been sitting in my main tank since i cycled it in there.

Anyway symptoms are. It kinda looks pregnant huge belly my mate told me that was a sympton of dropsy and thats why he was worried. And also there is a white patch covering the lower half of its tail fin.

any advice would be great thanks guys

 

[caino]

any1?

 

[WILDER]

Is the white patch fluffy, or just a bleach out patch, sounds bacterial with the bloated tummy as well.
Keep a look out for a bent spine, cysts on the bellys that go to a point, and red or blue area beginning to look bleached out.