I'm sure when we were fish n00bs we have all had our stupid moments with fish. Such as not acclimating or no water changes and just adding to make up for evaporated water.
Well, let's share them.
(don't be embarrased)
Mine was when I had 2 red belly pacus like 1 and a half year ago, I was doing a 100% water change and didn't know where to store them, they were only about 2-3 inches. So I went to my garage, found a plastic storage bin, washed it out, filled it up with hose water, and dropped the pacus in there. They were frozen, didn't move the slightest. I started crying my eyes out (yes at 14 years old) and I didn't know what to do because I loved them. Well about 20 mins of freaking out, I finally filled the tank back up with water and decided to put them in the new tank, even though I thought they were dead. Hey, worth a try. They started swimming around happily. Ever since that, they grew like .5 of an inch every 2 weeks.
So after a couple months they got too big and I gave them away to a bigger home in the petstore with some other pacus. 
Well, let's share them.
(don't be embarrased)
Mine was when I had 2 red belly pacus like 1 and a half year ago, I was doing a 100% water change and didn't know where to store them, they were only about 2-3 inches. So I went to my garage, found a plastic storage bin, washed it out, filled it up with hose water, and dropped the pacus in there. They were frozen, didn't move the slightest. I started crying my eyes out (yes at 14 years old) and I didn't know what to do because I loved them. Well about 20 mins of freaking out, I finally filled the tank back up with water and decided to put them in the new tank, even though I thought they were dead. Hey, worth a try. They started swimming around happily. Ever since that, they grew like .5 of an inch every 2 weeks.
So after a couple months they got too big and I gave them away to a bigger home in the petstore with some other pacus. 
. Did a quick water change, and everyone was ok.