Krill oil is a source of certain types of
Omega 3 oils. There are different ones.
Fish oil contains two types, and flax seed oil and hemp seed oil, for example, supply some as well. Now, I have a personal objection to krill oil, which is, krill are being killed off to get this oil and they are the food supply for most of what lives in the ocean, especially the larger creatures. Krill are tiny crustaceans and so it takes millions and millions of them to make some oil.