White lump on tetra's head.

[fishygurl]

Hi,

I have a 25 gallon tank with lots of Java fern.

Water quality has been stable for years, nitrates are around 20. Ammonia and nitrite are 0.

One of my serpae tetras has a white lump on his head. It is not underneath the skin, its on top. It doesn't look cottony like most fungus I've seen, its much more solid.

I can't figure out what it is, and so I don't know how to treat it

Thanks in advance

 

[mfdrookie516]

can you get a decent picture of it?

 

[fishygurl]

No, not really. I tried.

 

[happygirl65]

Does it look like salt? Is it flashing or trying to scratch on anything?