I am a newer fish enthusiast and I need advice, I set up my tank about a month and a half ago and last week I finally put some fish in it. I went with fancy guppies and brought 6 home (I have a 5 gallon octagon tank) today I noticed one of them lost their tail. I have checked out a few posts on it and it seems not totally uncommon and they can grow back but I would like a second opinion on if you think he looks healthy and alright. He seems to be swimming fine as he can make it up and down the tank. Any advice would be appreciated, thanks for your time.