So a while back I set up my first tank, unfortunately I decided to listen to a petsmart employee. Long story short, I now have a 10 gallon with 3 zebra danios, a female guppy, and a male betta. They were all getting along fine for months and now my zebra danios have gotten aggressive. The chase each other constantly, they go after my guppy, and they fin nip my betta. I have been trying to find them a new home but it's not working out. Is there anything I can do??