Please Help: White Betta Turning Red

Hello, I am very new to forums but I am concerned about my Betta. His name is Kirby and I've had him for 3 weeks. He lives in a 10 gallon tank that has a filter and a heater that keeps it at 78 degrees. unfortunately I did not cycle his tank but I did run the filter for a day before I got him. I did a water test today and ammonia came at around 0.25 ppm and nitrite at 0 ppm. I do 20 percent water changes weekly and will be doing one tomorrow. He is white betta with half moon fins, yellow scales on his face and forehead, and black under his chin by where his gills meet under his neck.When I got him I had all kinds of plastic plants in his tank. I thought that he could cut his fins on them so I took them out. I have some live plants in a different tank that I'm waiting to put in his tank. Over the past two weeks I have seen red appear on the base of his tail fin, but not on the scales, it's on the fin. They are short streaks of red. Then there is now also a tiny spot of red on the tip of his tail and on the tip of his dorsal fin and now a little streaks on his long belly fin.
I saw in a video of a Betta that looked very similar to him. Even had the same yellow on his face. In the comments someone who seemed knowledgeable in betta care said that that betta could be a marble Betta. Since my betta looks so similar to that one, I was wondering maybe it could be that? Or maybe it is burns or cuts, idk. he can't cut his fins on anything really now that he doesn't have much decor in his tank.
Also his overall activity is quite good and he's been eating well. And I have the light on in his tank from about 4 pm to 9:30pm, and he gets sunlight from the windows in my bedroom throughout the morning (of course the tank is not right beside the window though)
Any suggestions or ideas about what this could be? And what I can do if it is a bad thing?
Thank you for reading!

 

Pictures please

 

Over the past two weeks I have seen red appear on the base of his tail fin, but not on the scales, it's on the fin. They are short streaks of red. Then there is now also a tiny spot of red on the tip of his tail and on the tip of his dorsal fin and now a little streaks on his long belly fin.

pics would help a lot. but red streaks usually aren't a good sign.

you tested that water so that is good. but you didn't mention what the nitrate level is.

when in doubt do a large water change, 50% or more.

 

here is him today. I hope this link works. The red areas used to be white.

I can test the nitrate right now, will update soon. And I'll do the ph too.
Thanks for responding!

 

Ive read its normal for young white bettas to turn pinkish, reddish to shades of purple. Do you know his age? How is your water reading for nitrite and nitrate. Could be a build up in the water affecting his coloring

 

The current ph is about 7.4 and the nitrate is 5 ppm.

I am not sure of his age as I got him at a pet store. Also, one of his long thin spiky fins is permanently curled, it was like that when I got him. I don't know if that affect anything but it's like that.

 

I am not sure of his age as I got him at a pet store. Also, one of his long thin spiky fins is permanently curled, it was like that when I got him. I don't know if that affect anything but it's like that.

You can't upload a pic?

 

U can see it in the pic I sent in one of my previous replies. I hope the picture works, I've never sent a picture on a forum before, sorry

 

U can see it in the pic I sent in one of my previous replies. I hope the picture works, I've never sent a picture on a forum before, sorry

HI there! I just looked at the picture you posted and I think I know what's going on with your betta. If you bought him from a big name pet store, like Pet Smart, Walmart, PetCo he should be about 7 months old, this is when they choose to sell them because they are colorful and have their fins. However, he is still growing and that means that his color may change. That red looked normal, in my opinion, from what I saw in the picture. As long as there is no blood in his water and he isn't moving sluggishly he should be fine. I have a betta now who did the same thing after I had him for about a month. I freaked out too, I think that's the only normal thing to do when your betta randomly starts changing colors. I took him to a vet who told me that he was just a little slower to gain all his colors, but he would be fine as long as he wasn't refusing to eat, swimming lopsided/sluggishly or bleeding. I think the same thing is going on with your betta. Just keep an eye on him for any abnormal behavior.

 

Thank you so much! And thank you everyone for responding. I am relieved that he is just changing colours and isn't sick. Even today more red has appeared, more on his dorsal and on his one long thin spiky fin. Thanks again!