Hey everyone I won 3 goldfish from the fair about 3 years and have been keeping them in a 5 gallon aquarium, which I know is way too small. So I have decided to buy one of those blue plastic storage bin things and raise them in there. I would also like to cut out a drain on the bottom so I can change the water. Ok, so the point of this post is... How do I cut out a drain on the bottom? I know just cut a hole, but how do I make a plug to go over it when there is water in it??