what’s the bump on my bettas fin

That looks bad. It might be a cancer tumor, just like humans, fish can also get cancer. There might be something wrong with his diet, water conditions and/or a virus. Unfortunately, the cure is VERY complicated. A licensed and experience vet in tropical fish can only take the tumor out.

But also, it MIGHT not be cancer. Cancerous tumors are pretty rare, especially in bettas. It might just be an abscess. This can be the cause of swim bladder disease, fluid retention or constipation. If he is showing any signs of lethargy and/or not wanting to eat, there might be something wrong (one of these sicknesses shown above).

Please fill out this form so we can figure out what it might be.
Housing:
How many gallons is your tank?
Does it have a filter?
Does it have a heater?
What temperature is your tank?
Does your tank have an air stone or other type of aeration?
Does your Betta have tank mates? What kind?

Food:
What food brand do you use?
Do you feed flakes or pellets?
Freeze-dried?
How often do you feed your Betta? How much?

Maintenance:
Before your Betta became ill how often did you perform a water change?
What percentage of water did you change?
What is the source of your water?
Do you vacuum the substrate or just dip out water?
What additives do you use other than conditioner? What brand of conditioner?

Water Parameters:
What are your water parameters? Please give exact numbers. If tested by pet store please get exact numbers. "Fine" or "Safe" won't help us help you. Important: Test your water before the regular water change; not after one.

Ammonia:
Nitrite:
Nitrate:
pH:
Hardness (GH):
Alkalinity (KH):

Symptoms and Treatment:
When did you first notice the symptoms?
How has your Betta’s appearance changed?
How has your Betta’s behavior changed?
Is your Betta still eating?
Have you started treating your Betta? If so, how?
Does your Betta have any history of being ill?
How long have you owned your Betta?
Was he or she ill or suffering some sort of damage when purchased?

Your fish is your responsibility.
When seeking help be thorough as members give advice based on the information you provide. While we have many knowledgeable fish keepers here, please remember that members' opinions are their own and that it is up to you to determine the best course of action for your fish. We are not responsible for any consequences resulting from following the advice you receive here.

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