Same family as seahorses. They are very hard to find (a friend found this one): you can tell by the size of the grains of sand and blades of grass how big it is. I found a juvenile one myself the day before, but I lost it before I could catch it with a photo. Imagine a piece of thread about 2cm (3/4 inch) long: that's how big it was. I know, usually fish stories about the one that got away are towards the other end of the bigness spectrum!