I'll be honest, like the others, I have never qt'd anything in over 10yrs of fresh or marine tanks. For the same reasons the other ppl have mentioned. I had ich/velvet in my 10g a few mnths back,it was the first time I ever had an issue. The fish my husband baught was from a store I normally will not buy fish from because, well I simply don't care for the conditions their livestock is in, the lack of knowledge of the staff etc etc. The fish showed signs of illness 2 days later and i lost it and my purple firefish within 4 days. It sucks but it was a learning experience. 1. Buy from reputable places 2. Really pay attention to all the fish in the tank to prevent bringing home a sick one 3. Try to find out when the store received their stock...don't buy a fish around that time. Some stores don't acclimate and sell immediately which is an issue.