I think the silky is most curious shark there. He will swim right up to about 6 inches of us before he turns. I have been bumped by the sand tigers but I think they are just not paying attention to where they are going or they just dont care if they run into us. But the sand tigers dont look like they are even paying us any attention, but that silky watches us closely and gets right up and personal. My girls are doing great I have to get a male to go with them. I have been working to get my Phos down to 0 and Cal up to 400 and finally have that done so I am hoping my tank will start looking good instead of just green and brown algae covered rock.