Some people who can't hack fish oil have switched to krill oil and find it's ok.
Also, there seems to be a difference in fish oils. I don't know what brands are better than others, (and some have problems with capsules but not liquid, and vice versa). But I have run into one brand that upset my stomach, even though a few others caused me no problems. So maybe try a different brand?
I agree wholeheartedly with you, Jody,
Many people can tolerate one brand of any supplement, over another brand.
I take Thompson's Pure Salmon Oil (NZ company). 3 x 1000gr in the morning & 3 1000gr in the evening (total 6000gr).
Flaxseed oil also is high in omega 3 (but very expenisve & you need to keep it in the fridge & use fairly quickly - it goes rancid fairly rapidly). I prefer to buy organic flaxseeds (much cheaper) & grind them fresh every other day. I keep my flaxseeds in the fridge. You DO need to grind them, though. The tough outer shell cannot be broken down by the stomach & the seeds will go straight through your digestive system & down the toilet bowl if they aren't ground first.
I eat organic walnuts every day (& next in line in the nut selection is macadaemia nuts).
I also have a couple of meals of fresh salmon every week. And there's John West tinned red salmon on my shelf for occasional salmon & salad lunches. John West is my favourite brand, but there are plenty of cheaper brands on the supermarket shelf.
There are other non fish sources of omega 3's.