Your nurse said that because like all fish oils, krill oil is a natural blood thinner. To what extent, I have no idea. I'm still trying to figure that out.
Krill oil has other health benefits than fish oil. Specifically it contains Astaxanthin, an antioxidant. Dr. Mercola is a big fan of krill oil and you can read his comments about it here:
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krilloil.mercola.com]
Before you run out and take krill oil, however, Dr. Sears is NOT a big fan. He says most of these krill oil supplements are toxic and don't contain nearly the benefit they claim. Bear in mind, he sells fish oil supplements

I wish I could find the video he made where he talked about this but I couldn't. I remember thinking his argument made sense so I stopped taking krill. I only take fish oil now.
Travis