I figure if you take the fish back in the same bag you got him in and explain your situation to the Petsmart employee, they'll probably refund you or give you store credit for the fish. That's what I'd do at my store so hopefully they'll be understanding. Also, if the other platies haven't been bothering the betta yet, I'd think they probably won't start. Since you have three of them even if you were to take one back, they'll be fine and won't get lonely. Do you know what the sexes of your platies are? If you have two females and one male, they'll probably find other things to do rather than pick on your betta, if you know what I'm saying.
- Jolly Roger, halfmoon betta boy & ivory snail, bronze and sterbai corydoras catfish, neon tetras (15gal)
- Wanda, pale yellow veiltail betta female (5gal)
- Benedict, multicolored halfmoon plakat (3gal)
- Sparky, questionable tail type and gender (2.5gal)
- Neon, tiny betta baby (1gal)
- Marsha, multicolored female veiltail, and Capt. Morgan, multicolored dumbo plakat (div. 20gal)
- 10g community tank with a ton of balloon mollies
+ cats, gerbils, rats, geckos, snakes, a frog, and a dog.