You can find many cars with fish stickers on Australian roads. There are many stories connected with it. The following link helps you to understand it better. http://www.christianitytoday.com/ch/asktheexpert/oct26.html
Also family car stickers are popular in Australia. If you are interested to have one family car fish sticker, you can download the following and get it printed from a Car Sign Guy and stick it ☺
Fish Family Car Sticker