dailyfishtips:

Bettas are intelligent fish and will often become bored, especially in a small tank. But there are a lot of enriching things you can do to combat this. A few ideas you can swap out every few days:

• Draw pictures on their tank with dry-erase markers for them to investigate
  
• Put colored sticky notes on their tank in different positions
  
• Put a clean ping-pong ball in their tank for them to push around
  
• Rearrange their decor every week or so
  
• Shine a laser pointer into their tank for them to chase
  
• Show them a mirror for a few minutes every day
• Give them living food to hunt down, such as live brine shrimp, daphnia, or wingless fruit flies
  
• Teach them tricks!