I was being a bit facetious: what the image is showing is a koi pond. However, when you put it in terms of increasing your home security, the first thing that comes to mind is digging a moat around your house, which I found hilarious.
The 18th of July is
Crime Prevention Day!
A commemorative day established on this date by the Secom company because of the pun with "crime prevention"!
The pun:
Crime prevention → bouhan → bouha(n) → bou(pronounciation of the 棒 kanji, which means "stick", therefore 1) ha(8)Let's try to be aware of how to make it hard for burglars to break into our houses
