Thank you for the heads up. That's great advice.Just a warning on doing this. Make sure you can see the inside of the bottle where ever you place it. I put one in a tank 7 years ago and have zoas covering it. I put it on a angle and place it between two rocks. A few months later my tank crashes. When I pulled out the bottle I found a ton of dead hermit crabs that had been trapped in the bottle and died. I wasn’t able to see them because of the angle of the bottle and the coral covering it. Just a word of caution when considering placement.