Oh, Black sharks. I thought the name sounded familiar. Yeah, they're around, I think there are 2 fish stores in Wellington with them recently. I had one that was probably bigger than 20CM. He was good until about that size then he killed my Polypterus, my green severum, gold severum, a few other fish. :an!gry Gave him to someone else with a bigger tank with bigger fish and he started attacking theirs, they sold him to a pet shop after a few days and last I heard he's out in Wainui in a tank on his own IIRC.
Big beautiful fish though.