The galaxy koi is small so he is probably just 3-4 months old same with the rosetail. My giant betta had unfortunately passed while I was at work, moved him to a small quarantine tank to watch him closely.
I gotten two Halfmoon dragon bettas, a red and a black marble. I also decided to swap gravel to fluorite black sand(finely ground clay). Tank is a bit cloudy and there’s a layer of dust on the sand and plants now but I’ll do another water change in a few days.
I’m redoing this tank and removing the divider and moving bettas around. Giving one of my giant bettas to a coworker and moving the other giant to the 10 gallon and the two dragon bettas to the divided 20. I did order an Aquaclear 20 for the tank but it has massive cracks on it. I got it from chewy and they are sending me a replacement for the broken filter. Means extra parts if need be in the future.