I was just offered a 20g aquarium for free. Which sustained a crack while it was being moved around. It was bumped into a book shelf and one of the corner panes got a small crack. The owner says it doesn't go all the way through the glass and they cannot feel the crack inside of the aquarium or outside. I was wondering if it would still be safe to use this aquarium for fish? I havent seen a picture or looked at it yet but it was described to me as a 1inch line in the glass from bumping the bookshelf. They have some other equipment they said I could have also I'm just wondering if its worth taking the tank. I picked up another 20g the other day that is way to scratched for me to want to use. So I'm looking for a replacement for it.