If using frozen fruit, allow to thaw first to room temperature.
Line up 4 (25 ounce) bottles with flip top lids or other air tight bottles.
Puree banana with a fork. Pour 3 tablespoons banana puree, 3 tablespoons chopped pineapple, and 3 tablespoons chopped mango into each 25 ounce bottle.
Using a funnel, pour freshly made homemade kombucha into each 25 ounce bottle leaving 1-2" head space.
Let bottles sit out (at 75° - 85°) 3-5 days, making sure to pop the lids each day to let out the pressure of the carbon dioxide. Taste each day to test its flavor and fizziness.
Notes
Use only freshly made homemade kombucha that hasn't been refrigerated yet.