Question: what do betta fish play with?
Answer: Aquarium plants. Ok, they may not seem like toys to us (we will get to those ones later), but to a betta, aquarium plants can be like a jungle gym! ... 
Betta hammock. ... 
A Small Mirror. ... 
A Floating Log. ... 
A Sinking Ceramic Log. ... 
Fluval Moss Ball. ... 
A Ping Pong Ball. ... 
R2 Fish School Complete Fish Training Kit.