Hey there... I bought 3 fish (1 white with little orange in the fins, one half white half orange and one full orange) the full orange one died about 2 weeks after i got them i don't understand why, i do 50% water changes every week and use water conditioner, now the half orange half white is turning black, first it was the fins now it's turning into his body.... But the white one is good. My dad said that when he got back into the store because he wante to buy a new fish that all the fish were in quarentine (it's been 3 weeks since i got the fish). What is happening ? Is it a disease ? Is it anmonia problems ? I'm getting frustated and sad...