Remember when doctors dropped the big cholesterol bomb? Not a bomb made of cholesterol (that’d be gross); we’re talking about the news that there’s such a thing as good cholesterol, and that to get it, you have to eat lots of fish.

The more fish you eat, the healthier you are, right? Well, it depends on what fish you’re eating. One of the most common fish on the market actually might not be all that good for you after all. We’re talking, of course, about tilapia.

At some point along the way, tilapia leaped up to the No. 3 most-eaten fish in the United States. It’s a freshwater fish, and it’s easy to farm, so the prices have dropped. Even better, there’s no need to overfish tilapia. You can always just raise some more in your tidy outdoor ponds.

But as with every nutrition fad, the big difference is which tilapia you’re actually eating. Some is fine. Some is a little less fine. Regardless, none of it would qualify as a “superfood.”

Anyway, here are a few reasons you might want to stick to tuna instead of filling your freezer with this cheap and tasty farm-raised fish.

1. Most tilapia does not pack the omega-3 “good” fats as well as other types of fish.

If you’re eating fish for your health, you’re probably after the omega-3 fatty acids. That’s the “good” fat that can give your heart and brain a boost. Due to the controlled diets of farm-raised tilapia, though, this fish often makes a pretty weak showing with omega-3 levels.

Wake Forest study really kicked off the backlash against tilapia. The 2008 research paper found that tilapia raised on farms in Central America and China (which make up most of the frozen filets you’ll find in the supermarket) is actually quite low in omega 3s. Even worse, it’s pretty high in omega 6s. When you don’t get the right ratio of 3s to 6s, the later fatty acids earn their reputation as “bad” fats that contribute to heart disease and diabetes and a whole host of health threats.

That’s not to say that tilapia is unhealthy on its own. If you’re after those omega 3s, though, you’ll be better off sticking to salmon, tuna, and trout.

2. Densely farmed fish might be treated with pesticides and antibiotics.

When you make your living selling fish, there’s one surefire way to boost profits: Grow more fish.

If you do this by crowding the fish in the same small pools, though, you end up with stock that’s prone to infection. The solution that many large-scale growers turn to is blasting their pools with antibiotics and other chemicals.

Michael Fenster is a doctor who decided to stop eating tilapia outright. He explained his choice to Fox News Health in April 2016.

“A recent study sampled imported seafood and found imported tilapia treated with oxytetracycline…” Fenster said. “Other studies have found tilapia from China treated with malachite green and nitrofurans.” (These are antimicrobial and antibiotic chemicals.)

“While the levels found were below the regulatory limits, studies have shown that such usage can promote the development of bacterial antibiotic resistance. Humanely and naturally raised products taste better and are, quite simply, better for you,” Fenster continued. 

3. Farmed tilapia might not be very environmentally friendly.

Tilapia thrives in warm environments, which places colder U.S. breeders at a cost disadvantage. As a result, “almost all” of the frozen tilapia you’ll find at the supermarket comes from China, reports Men’s Journal. Fresh tilapia filets are likely to have been bred in Central America, where they can live in outdoor pools.

Massive farming practices in low-regulation areas aren’t great for the Earth. Some growers clear-cut forests to make room for fish tanks. Others flush antibiotic-laden water into surrounding waterways. Even worse, according to the Washington Post, a 2009 report from the U.S. Department of Agriculture found that fish bred in China “are often raised in ponds where they feed on waste from poultry and livestock.”

That’s not good for streams and rivers. It’s also not good for our appetite.

Before you panic, though, remember that not all tilapia is raised in hellish conditions. There are plenty of providers of high-quality tilapia out there, and the fish remains a decent choice for lean protein. Before you swear off the stuff forever, it’s worth seeking out a higher-quality filet.

Just don’t depend on tilapia for your omega 3s, and you’ll be fine.