I have unintentionally become pescatarian recently because I've come to realize that fish have a lot of nutritional value. So far, my meal plan looks like this:
Breakfast
3 eggs
1 slice of Ezekial bread toasted
Mixed berry smoothie with banana, peanut powder, collagen peptides, chia, creatine, non-fat greek yogurt, and water
Lunch
2 tin cans of sardines, mashed
Non-fat greek yogurt
Tzaziki sauce
Lemon
Black pepper
2 slices of Ezekial bread toast or one ezekial tortilla, depending on my mood
Dinner
Shrimp kebabs made with olive oil and veggies
1 corn roll or asparagus
Some days I'll switch out my dinner for a salmon salad / salmon wrap, or I'll change the shrimp kebabs for a shrimp ceasar wrap with a nice avocado oil based dressing. Being pescatarian is really great because it's easier to make, shelf life lasts very long, and it's generally cheaper than buying meats.
I checked a can i have of Brunswick brand sardines in olive oil. That has 16% DV or 370mg. If theirs is similar, it looks like they may just get other sodium from the bread or tortilla or when they do caesar and they might be fine.