Betta with bloody spot on tail

Question
Hi Jaymie. There is a red bloody looking spot on the end of my betta's's tail. I thought at first it was early fin rot, it was the only thing I could find about red fin edges, but he has no other symptoms of fin rot. His tail is not getting shorter, his other fins look fine, and he's active and eats well. He's in a 5 gallon tank, heated but not filtered, and I do regular water maintenance to keep it clean.

The red spot is only on a tiny part of his tail. It looks like a small bloody dot. I think it has to do with a past injury that happened about 5 weeks ago. I used to keep gravel in his tank, and one day when I was doing a partial cleaning, he had freaked out a bit and slammed his tail into the gravel. It got cut up pretty bad, a little part of the fin got ripped away leaving a jagged looking hole with red along the edges which I assume was blood. Most of what was ripped away has grown back, but a tiny part stayed kind of red, but it looked like it was healing. But yesterday I noticed it got a bit bigger and was a bright red. I think it might be an infection or something. I did a large water change this morning which I think helped because it doesn't look as bright red anymore. Do you think the red spot could just be a flare up of a previous injury? Will clean water be enough to heal it? Thanks.

Answer
Michelle,
It could still be from the injury. I suggest putting some aquarium salt in his water until it heals. The ratio is 1 teaspoon per gallon of water. When you do your water change, make the salt solution. Only add the salt water in the replacement water. So to do this you take a gallon of water. Add to it 1 teaspoon of dissolved aquarium salt. If you take 2 cups of water out of his tank, replace it with 2 cups of salt water. Make sure the water going into his tank is the same temperature as the water in his tank. Keep him in the slat water for a few days. This will help heal the injury. Once he is better you will start removing the salt, since it does not evaporate with the water. You can do this by doing 25% water changes every 2 to 3 days until the salt has been removed.