Betta Has Bump On Dorsal Fin

Hi. I am a first time betta fish owner. My purple-ish male betta fish, Olly, has aquired a large bump on his dorsal fin. It appeared one day. Nothing seems to be wrong with him, but it has me worried. I keep him in an about a little more than a gallon filtered tank with a few plastic plants, plastic coral, multi-colored rocks, and a small sign. The tank also has a heater on it. As I mentioned Olly is acting completely normal. I tried to watch the bump for a few days, but it hasn’t gone away yet. I have heard people talking about white bumps, but mine is black. I'm really worried. Is he sick? Do I need to get him any sort of treatment?
Any help would be greatly appreciated. Thank you, Ky.

 

Pic, please. The tank is too small. A Betta needs a minimum of 2.5 gallons and plastic plants will tear their fins. Only live plants or silk. A pic will help diagnose bump. Welcome!

 

Agree photo please, and also Welcome to FishLore! Ive never heard of a filter and heater for something less then a gallon... Bettas need at least 2.5gallons.

 

It says you don't know about the nitrogen cycle and that is important to the fish keeping world click the blue cycle for more info the basic version is fish poop and uneatin food is called ammonia this is toxic to the fish bacteria comes and eats the ammonia this bacteria is called NitrITES this is also toxicthis bacteria poops and another bacteria comes and eat that poop this bacteria is called nitrATES which is beneficial to the tank and is not toxic in low levels

 

Thanks for the information. I will definitely try to get him some new plants, and a new tank if I can. Here is the pic you asked for. It’s that black dot near the base of his fin.

 

I don’t know the exact measurements of the tank. That was just my estimate.

 

Could the nitrogen cycle have something to do with his bump?

 

I have kept monitoring it and it seems to have almost popped or deflated. To me it looks worse. It almost looks a bit white now. Please help!!

 

If it doesn't seem to be affecting him, then leave it. Since it popped, just keep the water super clean to prevent infection and upgrade to a 2.5 gallon tank with silk or live plants because those other decorations could've caused the bump. As long as he's acting fine, don't try to fuss with it. If you're like super worried about it, Foo the Flowerhorn had a video about his betta with a tail tumor and he surgically removed it.