Should a cat with IBD take an Omega 3 supplement or can is cause vomiting?

Enzo was diagnosed with IBD a few years ago. Once I switch him to a limited ingredient diet he had no vomiting (which was his issue). I recently started him on a daily omega 3 supplement (Nordic Naturals) and added a second kind of food, Blue Freedom Grain Free Indoor Mature Chicken.

He has thrown up twice over the past two weeks. Not every day like he had been before discovering the IBD, but twice concerns me.

Do flare ups occur with IBD without warning? Could it be either the new food, the omega 3 supplement or both?

Thanks for any help!

All cats should be on a omega supplement. While it could be the supplement, it's probably the food. Blue is not good quality food. The company has a bad reputation and I wouldn't consider it a limited ingredients food that would be good for an IBD cat. IBD cats typically do better on either homecooked, raw, or foods with simple ingredients like Feline Naturals, Tikicat, or Ziwipeak. 

Thank you for replying! I had him to the vet today for full blood work just to be sure nothing else is going on, but you're right, I think it was the food which I stopped yesterday. The vet said to stick to the one protein that wasn't causing problems (Turkey). So I ordered a case of Wild Calling Turkey and I'll keep him on his merrick limited ingredient turkey since it doesn't upset his tummy. Great to know about the omega, I was hoping it wasn't the supplement causing the upset as it has so many benefits. Thank you again! Also, I have looked at Tikicats but he had several teeth removed and only eats pate.