THE ANGRY FISH by Justin
This is a reflection (flip, mirror) tessellation. You can tell it's a mirror tessellation because under each fish facing right is another fish with the same shape but facing left.
Fish are a very popular theme in tessellation art. Why? Well, they come in a great variety of shapes and sizes, and their fins and bodies are flexible. So, it's easy to make them tessellate. Here's an essay about why fish are a great theme for tessellation art.