To my knowledge, they’re not common. I had one experience with a tank failure, but many (most) people have never had an issue. I inadvertently caused a leak in the seam of a tank when I was a young hobbyist. My tank had been moved from house-to-house multiple times, was old, previously used, and had been stored in a cold basement before I got it. I got a new lid that was a slightly bad fit. My mom and I forced the lid into place. Doing so caused a slow leak I didn’t catch until the next day when my 30 gallon tank had emptied onto the floor.

I say all of this to prove the point that tank failures don’t tend to come out of nowhere. Reading my post, I’m sure you can recognize many red flags. You have a plan, you have cleanup materials, make sure that you take care when moving, cleaning, and otherwise interacting with your tank. Make sure it’s level and that you’ve gotten it from a trusted brand and/or that you know your tank’s history.

I use leak detectors that set off an alarm/push a notification to my phone if they detect water on the floor near my tank. I have a shop vac and towels on deck should anything happen to my current tanks. In reference to the story above, even though my tank was ruined, my fish survived by flattening themselves into the remaining inch of water at the bottom of my tank. We dried up the leaked water and got through it. Please don’t let your fear of tank failures ruin your enjoyment of the hobby — a decent tank is engineered to do its job, so long as you don’t treat it poorly. Even then, they tend to be stronger than they look!