Is this Lymphocistis

[pfish]

It looks like it to me. The only problem is the fish has had this for 6 months and I thought it should go away in weeks. He doesn't have any other symptoms just these unsightly warts and strange bulge at base of dorsal fin. The warts appear to migrate from the lump and radiate out towards the edge of the fin and then disappear . The tumor(?) varies in size as well as the # of cysts (warts).
If it's not Lymph what is it? None of my other fish show any signs of disease
Thanks

 

[pfish]

No one has an opinion.

 

[skibum9884]

It certainly looks like it to me. Maybe it could be bacterial, but my first guess would be lymph.

 

[pfish]

Thanks for the reply: My only doubt is the length of time he's had it. From the literature I have read it should be gone in 4 weeks in 25C temp.
Has anyone heard of it hanging around for 6 mo.?