Okay so I bought a fish a little more than a week ago and now it’s starting to become very aggressive, is there any way I could trade it for store credit?

I'm sure they will exchange or refund.

Yes just call the store and explain whats going on to them.

yeah

Yes

Yes, I believe they will.

I buy fish from pet smart all the time and yes you definitely can. They have a 14 day live fisj guarantee with receipt and if your fish isnt compatible with your other fish then they should swap him for something else. One of our tanks is a 55 gallon plantes community tank amd we had bought guaramis for it because there should of been plenty of room for each of them but they didnt get along and it was stressful on the fish and me so we took them back and got something different. Make sure to tell then what fish you have and size tank so they can help you pick fish that wont become aggressive so you dont have this problem again. Or there is a great compability chart on line for freshwater fish to know ahead time who get territorial or aggressive and who lives happily etc

Just give them a call.

Call them, they will probably work with you.