toothfish; anyone tried?

After years of complaining that in spite of all the poaching and expensive licences being handed out, I have never seen it on sale, found it at my fish market today. $70 a kilo!! Still, couldn't help myself: phoned the broker; quick sale; and bought a piece the size of a cigarette paper. But what to do with it. Sashimi?? Anyone tried it or have a recipe. Told the flavour is very strong and to be careful what I cook with it.
Helpful advice needed. The fighting fish is already looking at it with mournful eyes. jwt