Reading through the April issue of Practical Fishkeeping (it takes a while for the UK magazine to hit the shelves here) I noticed a brief article mentioning research by Lukasz Pasco of the University of Wroclaw in Poland. His paper, Tool-like behavior in the sixbar wrasse, Thalassoma hardwicke, published in Zoo Biology, describes the sixbar wrasse smacking large pellets of food against rocks in order to break them intoo smaller pieces to eat.

I was a bit surprised. This is news? My moon wrasse (Thalassoma lunare) does that all the time. I give her Hikari Cichlid Gold large pellets regularly and watch her smash them against the rocks in the tank. It didn’t occur to me until reading the article that this behaviour is unique among my fish. I’ve seen many of my smaller cichlids trying to deal with the large pellets, but I’ve never seen one use a rock.

Unfortunately it isn’t of brilliant quality, but here’s a video of the behaviour in question:

It’s certainly interesting behaviour, though I’m not sure if it should be classified as tool use. Both species are from the same genus, so I’m wondering if other people have seen the same behaviour in other Thalassoma, in other genera of wrasse, or in other families of fish.

The sixbar wrasse is a very common sight when snorkelling on the Reef, and willl often be found swimming along behind snorkellers trying to feed on organisms in sediment kicked up by a snorkeller’s fins. It’s the only wrasse I’ve found doing that, though sergeants do the same.