All the fish will die.
All the fish will die.
Scuff it up with sandpaper to help promote algae growth. I know the piping well, its refereed to as inner-duct. Its sides are very smooth to make it easier to pull through ducts, and reduce the drag of pulling cable through it.
I got a bunch of this stuff too. I concrete it into buckets. But I never tested it and had no idea it would float. I still prefer hard wood. I mix them up some times.