Molly has large bump growing larger on side of body

[Jules.aqsrawsm]

Midnight, our female Molly, has had a bump on her side for about two months and the bump has grown larger within the past few weeks. I am thinking that it might be either a bacterial infection or a tumor. I have tried to find more information about what it could be but unfortunately have not been able to pin point what is going on yet. I have recently started Melafix, hoping it might help her. Anyone know what this could be? The pics show a few angles. From the side, the bump is REALLY sticking out very far.

 

[mikey11]

tumor

 

[Colin_T]

A bacterial infection would show up are red inflammation and would have killed the fish by now (after 2 months).

It is probably a tumor and if it has grown a lot more over the last 2 weeks I would probably put the fish down.