For the past 2 weeks I've notice a lump on my betta Stanley's belly right in between the two long fins that hang. I just noticed tonight that it's gotten big enough in the past few days, while I was out of town, that it has broken through his scales or stretched out between them. It looks like it's where his anus is but I can't tell. He keeps flaring at me so I think he doesn't feel well. I just got a dog and slacked on changing his water for almost a month but his tank is fully cycled with a heater and filter and I used Prime to neutralize any ammonia nitrites or nitrates. If anyone knows about lumps or tumor like this please help. I don't want my lil boy to die if there's something I can do to help him!