My Betta, Dont Know What It Is, Help Please

[crazycallum]

my bettas getting like a weird swollen bit on him cant explain it but dont know what it is, can someone tell me if anythings wrong?
heres picture
he seems to be acting fine apart from that

edit:

 

[crazycallum]

anyone fancy helping

 

[Loony Fish]

t looks like a fish lice. my koi got one once. think there are a lot of ways to treat them. do plenty of research.

 

[WILDER]

Fish lice will be disc shaped with legs.

 

[Sunny_Bee]

It could be a tumor, I can't see too well from the pic. Often these don't do any harm, they just grow.

 

[WILDER]

Lumps that suddenly appear are usually bacterial.
Does the lump look hard or soft filled with fluid.