Is my betta's fin discoloration a sign of infection?

[bloomr]

I'm dealing with a weird issue in my 10-gallon planted tank, home to my solo betta. The tank's about two months old, and my water parameters are looking good - pH 7.8, ammonia 0, nitrites 0, and nitrates 0. I'm using RO water with remineralization, which I stopped doing for a bit, and that might've started this problem.

My betta's a "black orchid" with blue and black fins that had clear tips when they grew out. But about a month ago, his fins started turning pinkish, and it's getting worse. I've been treating him with Kanaplex, and I'm halfway through the second round, but I haven't seen any improvement.

The tank's at 78F, with a sponge filter and a HOB, and some IAL leaves. I do a 30% water change weekly. My betta's been eating live blackworms almost exclusively for a month, and he's pretty active, but I've noticed him resting in the surface plants more often lately. There are also some escapee blackworms in the gravel.

I'm not sure if this is fin rot or something else. Is Kanaplex the right treatment, or should I try something else? I've attached some pics of my betta's progression - this is how he looked when it started, and this is how he looks now. I even pulled him out during a water change to get a better look on a white background.

Any help would be appreciated.

[folksea]

I think it's the start of fin rot. You might want to try Betta Fix, it won't hurt to add it to the tank. I've had experience with fin issues in my tank before, and Betta Fix helped. It's weird you're having this issue with plants in the tank, usually that helps prevent fin rot. How long have you had your betta?

[angelica]

I think it's possible he's just changing color as he matures. Those fins do look pretty healthy to me.

[sSjey]

I'm inclined to agree with angelica here. The fins genuinely do look healthy, I think it's just a color change as he matures.

[bloomr]

I've had him since October 20, two months ago, when I started the fish-in cycle. The red coloration still seems off to me, like an inflammation. His fins haven't died back yet, but I'm not convinced it's just a color change.

Could a diet of blackworms be affecting his fin color? I mean, the worms themselves have a reddish tint, like the brine shrimp that turn flamingos' feathers pink.

When I first got him, his coloration was different.

[bloomr]

Here's a photo of my tank's setup, I figured it might be helpful. I've got a pretty standard HOB and sponge filter going on, plus the IAL leaves for some extra filtration and hiding spots for my betta. The plants are still pretty young but they're growing in well, and like I said before, I've got a bunch of escapee blackworms living in the gravel now.

[bloomr]

I've had him since October 20, so only two months, and I'm doing a fish-in cycle. The red color just doesn't seem like a healthy thing to me - more like an inflammation. They haven't died back yet, true. I'm wondering if a fluffnut of blackworms could be affecting his fin coloration, you know like when flamingos eat brine shrimp and their feathers turn pink. The blackworms do have a reddish tint to them. When I first got him, his fins looked like this.