My darling boy King Popzy passed the other day and now his tank is empty. I was thinking of moving Prince Plum in but not until I know its safe. Popzy had dropsy and I'm treating the tank with api tc tetracycline right now. should I don other meds on the tank?

Ok, so I have a ten gal. tank, a very chill betta and a Marina Slim15 filter. My tank is on its way to being nicely planted with lots of hiding places. I have been finding a lot of mixed results about adding cardinal tetras to my tank. There are also two Amano shrimp in the tank already. I...