As a Type A, I know shellfish isn't the best for me.  But, my question is, can I take neptune krill oil (a type of shrimp) instead of fish or cod liver oil?

LorettaA,
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http://www.shokos.com/CryptomonadalesCGF.htm
ARTHRITIS PROTOCOLS
Use this protocol for 12 weeks.

BLOOD GROUP A

Frankincense (Boswellia serrata), 500 mg: 1-2 capsules with meals
Betaine HCl, 250 mg: 1 capsule with large meals
Fish oil capsules (3 grams of EPA plus DHA): 1 capsule, daily
Deflect A   (Lectin blocking formula): 2 capsules between meals
Sprouted Food Supplement (Live Cell A): 2 capsules daily
seems to be ok for As according to this protocol
http://www.dadamo.com/protocols/7.html

If your after the Omega 3s than you can try flax seed oil with lignans which is much nicer tasting then fish oil. I would be wary of any fish oil kept at room temperature when being shipped or in the store, because it is likely to be rancid. The best way to get fish oil is through eating beneficial or neutral fatty fish. I hope that helps.

I've never heard of neptune krill, so cannot comment.  And don't remember reading comments on specific fish oil supplements from the  blood type diet perspective for type As, but I take cod liver oil myself (Carlsons has a lemon flavor that is very palatable).