It's really surprising how many people don't realise where omegas come from and just default to "more fish". Fish get omegas from alge. Simply skip the middle man and all the nasty side effects that has in the form of animal exploitation and harmful substances for humans they contain.

Fish metabolize and concentrate the oil.

Cows eat grass for protein, we can't really skip the middle man and eat grass to get protein.

I don't know if it's true, but it wouldn't be unusual for there to be benefit from getting omega 3 from fish rather than algea because of something like this. AFAIK, we mostly only know about the benefits of eating fish.

Fish contains a lot of microplastics. Algae-based omega oils do not.