I bought 6 fishes 3 years ago, 5 of them are still alive and huge! I never have to worry for diseases, I just bought a bigger aquarium because of the size of my fishes and I was worry to add more fishes, concern of diseases etc. it was no problem at all! Its been 2 months since! Prior I had aquiarium and when I bought one fish at a different store, all of my othe little fishes died even the algae eater!