What happens if your Betta fish has a ball on neck?

Dropsy: Dropsy is a bacterial infection that causes fluid to build up in the body, causing the fish to appear swollen and bloated. Look for a pineconing effect as the scales stick out to make the body appear like a pine cone.

Parasites: If the lump on the neck of your Betta fish is small, round, and white, it may be a parasite. If this is the case, you will need to treat the fish with a parasite medication.

Tumors: In rare cases, a lump on the neck of a Betta fish may be a tumor. If the growth is large, dark in color, and does not go away after a few weeks, it is likely to be a tumor.

If you are not sure what is causing the lump on the neck of your Betta fish, it is best to consult a veterinarian.