Guppy Died Suddenly

[cwa]

My fish had been in a 16g tank, and the most recent additions were the 6 guppies. They were added less than a week ago. They all have been doing great. Transferred them all to a new 55g tank last night and within an hour, one of the guppies couldn't swim well. He would swim up and then fall upside down and lay on the bottom on his back until he got another burst of energy to swim up again just to fall again. I removed him from the new tank and put him back in the old tank, where he died. All other fish look fine. I have no idea what could cause this. I see no signs of illness.

 

[CammyP]

Could just be stress of the move

 

[Lettybetty]

My fish had been in a 16g tank, and the most recent additions were the 6 guppies. They were added less than a week ago. They all have been doing great. Transferred them all to a new 55g tank last night and within an hour, one of the guppies couldn't swim well. He would swim up and then fall upside down and lay on the bottom on his back until he got another burst of energy to swim up again just to fall again. I removed him from the new tank and put him back in the old tank, where he died. All other fish look fine. I have no idea what could cause this. I see no signs of illness.

when you moved them did you put them in a bag and float them first?

could be that he was the weakest one and the stress of moving killed him