Fin rot on betta?

Hi I'm new to this forum! I'm new to this hobby and I started with a betta in a 5 gallon. I cycled the tank before i bought him. The tank is constantly 78 degrees and has a filter. It also has live plants, an assassin snail, and some pond/bladder snails. I bought my fish a couple weeks ago from a local fish store. After i brought him home, i noticed a black spot on his fins and some black on the ventral fins. I've been watching it and i dont think its gotten worse. Does this look like fin rot and if so, how do I treat it? He is very active and has a good appetite.

Sorry the photo isn't great, he wanted dinner so he was trying to see what I was doing.

Btw the 5 gallon is temporary, soon I'll be moving him to a 20 gallon.

I don't think it is finrot, the edges of his fins don't look ragged or frayed. His colors could be changing now that he is in a calm and stable environment. Once a betta is no longer stressed from being in the store or shipped they tend to color up a bit more. One of my bettas went from mostly grey to dark blue and black.

Circus said:

I don't think it is finrot, the edges of his fins don't look ragged or frayed. His colors could be changing now that he is in a calm and stable environment. Once a betta is no longer stressed from being in the store or shipped they tend to color up a bit more. One of my bettas went from mostly grey to dark blue and black.

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Oh so the black on the edges isnt fin rot? I didnt think it could be part of his normal coloring. I was looking at photos from when I got him and realized it has actually spread...

I was looking at the tail and anal fins, can't tell on the other ones. Someone else might be able to give better advice, though. I have only dealt with finrot once before.