Also, how old is the fish? I know orandas are said to not start growing their wens until they're 1 or 2 years old (although I have seen mighty little fish with mighty big wens!)
My oranda is good sized (3 inches, maybe 3 and a half?) and his wen is just like, non-existent, so I figured he must not have the genes for it.
Then out of nowhere, four months after I got him, his wen is starting to grow

I'm super happy.
I feed them LOTS of food though, because I want big fish and I finally have the space for them!