In our last column, Jenny wrote about peanut worms; animals which rank highly on the fascination index, but are not beautiful, except perhaps to their mothers. But the little sand diver, (Limnichthys fasciatus) ranks highly on both scales.

I first became aware of this fish doing scuba surveys of the reef life at Bannisters Point, near Mollymook. Crossing small isolated patches of sand in the shallow rocky reef, I noticed small puffs of sand erupt as I cruised slowly overhead. Closer inspection suggested fish diving into the sand, except that I never actually saw them. Then one day, for just a few seconds a small striped fish sat on top of the sand looking at me, before it too disappeared. Too bad that my heavy SLR camera was at the other end of the survey tape. Enquiries suggested a sand diver, but there was no proof for positive ID.

Now we carry small compact digital cameras at all times when surveying. They have their limitations, but at least we have a chance of nailing a pic of something special mid-survey. And so it was when surveying very recently in the small sanctuary zone on the northern side of Jimmies Island I came across more sand divers. Once again, with a bit of patience I found an individual that was braver (or more foolhardy?) than the others, and this time, I had a camera handy. But taking a pic is easier said than done. We are talking about a fish maybe 40mm in length, not much thicker than a match, whose colour pattern matches almost perfectly the sand and shell grit it hides in. When you take your eye off the fish to find it in the camera’s display (to frame the picture) it disappears! So, back to the sand, relocate the fish (preferably “fixing” a position in relation to a prominent object like a large shell fragment), back to the camera display; find the shell fragment in the display, then the fish; then recompose and take the pic! Phew… but try it enough times and eventually you will succeed.

You might ask ‘why bother?’ when you can see such cool stuff in nature docos on the telly. Um… well, because it’s a challenge, and because it’s one of life’s little mysteries. My collection of fish ID books show only one painting and one pic of a dead specimen of a sand diver, so a more intimate portrait is of interest. Plus seeing one raises as many questions as it answers: what do these little fish feed on? What feeds on them (there are some voracious predators which can plough rapidly through the sand)? How do they move so fast in the sand grains, which would be like boulders to us?

My fish bible says this species grows to 60mm, is relatively common locally, and may be found “in sandy coastal waters to 25m, most frequently adjacent to reefs, or in shallow sandy rock pools”. With luck and a lot of patience, you too may be able to find it, perhaps with the aid of a snorkel in a deeper pool.

Clearly the little sand diver has evolved to fill a special niche; a tiny part of complex reef ecology. Sanctuary zones allow us to enjoy and study such relationships and habitats, as free as possible from the disturbing hand of man.