I was really dumb one afternoon and bought a pleco from Petsmart. Tanks looked good. The next day my Cardinal Tetras brokeout in Ich, and died that night. My hatchet fish school died the next day. My school of rasboras survived.
I went to Petsmart the next day and confirmed where it came from(the ich). The manager did not even know what it was. I had to tell him, then tell him in was in several other tanks. There was a clown loach covered in spots gulping at the top of the tank.
I lost 11 fish in 1.5 days. The manager did his best to make me happy. He comped at new filter for my upgraded tank, but it always hurts when you lose fish, especially when you've had them for a while. Anyway i learned my lesson i'll only buy fish from Worlds Under Water my LFS.