Did you know if you can find indian almond leaves or don't want to pay $9 for 10 leaves then their is something you can use for about a 10th of the price. You can use green tea decaffeinated bags. You can boil water and put the tea bag in, I then wait until it cools to the temperature of the tank that i'm adding it to.
So what does tannin in the water do for your betta. the fish feel better, safer, and can help promote
wellness. You can also use small pieces of driftwood in your aquarium for your tanins as well.