@lefty o Thanks. I'm kinda wondering if one guppy is bullying the others too much. He is trying to establish his dominance and won't leave the other two alone. Even in the 55 gallon now, he chases the other two around a lot. He may have stressed the dead guppy too much in the quarantine tank but I never noticed him being aggressive until after the one died. I'm thinking it's time to add more fish to the tank to help balance the aggression out some. I'm not sure if the LFS would take him back for an exchange or if he will calm down some if more fish are added.