6 Answers
Only for 2 minutes after which the Koi will eat the Betta. They are not compatible in anyway. Temperature, setup, etc. nothing makes them compatible. A koi should be kept in a coldwater pond, a Betta in a tropical tank. Bettas swim slow and hate currents. Kois dont mind currents at all. With the koi reaching a potential 3 feet (even 4 in cases) it will just see the Betta as food.
The water temperature the two fish need is quite different. The Betta is a tropical fish and needs a minimum of 2.5g of heated, filtered water while the Koi is a cold water fish that needs a pond size habitat.
I would discourage you from mixing the two.
yes they can if u acclimate them correctly, i have a 250 gallon tank with butterfly Koi under tropical heat with a lot of tropical fish, but it requires work to maintain the tank for both fish, you require a good clean up crew in your tank, and environment knowledge on how to make a cold / tropical community tank work. Koi and Goldfish are very messy, you need to learn some things before u mix and match.
no the koi would kill the betta, and kois need to be in ponds 1000+ gallons
no. koi fish are cold water fish and bettas are tropical.