Firstly, seperate the two fish. After you've done that here is a checklist of some things you may need.
. Two different tanks for each betta. Minimum of 1 Gallon.
. Water Condition to neautrilize any heavy metals in the water.
. A thermometer
. A sponge filter (optional)
. Decor and silk plants- plastic will rip the betta's fins.
. Live plants (optional.)
.Food: There are a large display of betta specific foods available.
After you have this, follow these steps to setting up both tanks:
. Put bettas into seperate containers and change the water 100% for each tank.
. Put Water Conditioner and Stress Coat in (this will help with the bite)
. Put decor and heater in tanks.
. Acclimate fish to seperate tanks.
.Check on fish an hour later, to see how they are doing.
Hope this helped!