Is this correct?

กินอาหารทะเลเป็นไหม Are you able to eat seafood? (Something I might ask if I'm afraid a friend doesn't like or is allergic to seafood correct?)

เคยกินอาหารทะเลไหม Have you ever eaten seafood? (In the history of your life)

ผมไม่เคยกินอาหารทะเล Does this mean I never have eaten seafood (in the history of my life) or does it mean I "never do" (indicating I have eaten seafood before but never eat it)?

Edited August 28, 201015 yr by ubonrthai

"กินอาหารทะเลเป็นไหม Are you able to eat seafood? (Something I might ask if I'm afraid a friend doesn't like or is allergic to seafood correct?)"

If the question is "are you allergic to seafood" or "do your personal beliefs allow you to eat sea food", then in Thai I would say

คุณกินอาหารทะเลได้ไหม

Using เป็น implies ability as in "can you (stand to) eat seafood" (more likely example: "can you (stand to) eat Rocky Mountain Oysters (calf gonads for the uninitiated)" or the one heard here all the time--โอ้พูดไทยได้ กินปลาร้าเป็นไหม Oh, you speak Thai, are you able to eat Pla Ra?

ผมไม่เคยกินอาหารทะเล means "I have never eaten seafood (in my life)" and has no particular implications about whether or not you would now, given the chance, eat same.

If you mean "I have never eaten seafood nor would I ever do so", I would say "ผมไม่เคยกินอาหารทะเล ผมกินไม่ได้" meaning "I have never eaten seafood in my life. I cannot eat it.(because I can't stand it or for whatever personal reason)". If further explanation is required, you could say, ไม่กินเพราะว่า ไม่ชอบ (ครับ) I don't eat it because I don't like it.

Is it possible that you are confusing เคย with ค่อย in your last example?

ผมไม่เคยกินอาหารทะเล I have never eaten seafood.

ผมไม่ค่อยกินอาหารทะเล I rarely eat seafood/I don't really eat seafood.