This site isn't especially positive about krill oil. There are a lot of things not to like about krill oil. The tiny shrimp harvested to make krill oil are important food for penguins and walruses.
Krill have to be very carefully processed to avoid contaminating the product with the toxic fluorides found in the shell. And krill oil is expensive.
But some recent research coming from a consortium of researchers in Finland, Italy, Norway, and the USA finds that krill oil may be especially beneficial for one group, overweight people who get the munchies.
The research found that fish oil and krill oil had similar effects for raising bloodstream concentrations of beneficial fatty acids. But krill oil has another effect on the endocannabinoid receptors of the brain.
These are the same brain receptors that respond to cannabinoids from marijuana. They activate the cells that send the message "Whoa. Dude. Gotta get some Cheetos."
In overweight people (whether or not they smoke marijuana), krill oil down regulates the endocannabinoid receptors so that eating starchy snack foods is less appealing. The research has not gone to the next step, confirming that krill oil helps people lose weight, but that will be studied in future research.
Should you take krill oil if the munchies sabotage your effort to diet? Well, it's worth a try - it you buy a high-quality product that's carefully manufactured to avoid contamination with shell fragments and ocean-borne toxins.