Some of the pre-made pastes, Maesri in particular, have neither fish sauce nor shrimp (dried, fresh or otherwise) and are vegan. We've used this brand and this type, massaman, before and I don't recall it being quite as spicy! Not searingly hot, but certainly had both Andy & I sniffing. I began to regret that I'd taken so much sauce that I had no plain rice to help relieve the slight chili burn. Andy used a can of light coconut milk, from Trader Joes, but I believe we used less curry paste in the past because the sauce was much lighter. This is likely why I recall it as being milder.
The best parts in it? The carrots I pulled out of the ground of the field next to my Mom's, the summer squash brought by AJ (from friends' CSA box while they're out of town... extras!), the red potatoes. The carrots were so sweet and lovely, I ate up bits of one while I chopped then up. The squash, a "butter stick" type variety (yellow zucchini) was really tender and nice in the curry sauce. Red potatoes always seem to be just succulent and lovely in massaman curry and these were true to form.