Fish are friends, not food, says Dory of Finding Nemo, PETA and vegetarians everywhere. Apparently Jeremy Piven has joined the club. The Emmy-award winning star of Entourage has not consumed anything with fin or flipper in over ten months.

“I haven’t had a piece of fish since the doctor told me to lower my blood mercury level,” he recently told People magazine. Apparently he was suffering from “mercury fatigue” this past winter, and was forced to quit a project in order to recover. His blood levels were six times the normal blood level for mercury; he must have been eating fish at every meal!

Actually, the actor reports eating fish twice a day for 20 years. That’s still quite a lot of fish.

And, like other fish friends, Jeremy says it’s not their fault they’ve been mercurized. “For the record, it’s not the fish’s fault. It’s a manmade problem. It’s all the mercury being dumped.”

This is quite true; fish do not produce mercury themselves. They are, in fact, poisoned by humans, mainly through agricultural and manufacturing dumping or runoff into bodies of water, including by means of crop dusting and smoke stacks. So in effect, we can blame ourselves for making fish dangerous to eat.

Larger fish and older fish are typically more susceptible to being full of mercury. The FDA reports that most fish available in fast food chains and as frozen fish sticks are typically safe.

Piven went on to advise that women should not eat tuna, “especially when you’re pregnant.”

He is partly right on his research. The FDA recommends that women avoid foods with high levels of mercury such as shark, swordfish, king mackerel or tilefish. However, it also recommends that women, especially those who are pregnant, consume two servings of fish per week in order to receive the needed omega-3 fatty acids that are crucial to brain development.

If you are lucky enough to have access to omega-3s in other forms, such as flaxseed or supplements made especially for pregnant women, that might be a safer road, but growing fetuses do require these vital acids, so it’s important to keep them in the diet somehow.

The bottom line is that if you don’t want to eat fish, you don’t have to; there are plenty of other sources of both protein and omega-3s. But if you do, there are still safe choices you can make. Click here for a free printable guide to how much and what kinds of fish are safe to eat—as well as which kinds should be avoided.