I've been told that krill oil is a rich source of omega-3 and they're more available than those from fish oil?

Krill oil does have some omega-3 as EPA/DHA. However, the levels are much lower than the majority of fish oil supplements available in the market place. There have been no controlled clinical trials comparing exactly the same amounts of omega-3 from krill oil vs. fish oil to suggest that the former source is more available.