fish worms

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This black drum has parasitic worms in its muscle tissue. Would you pick them out or toss the fish?

Fishing and worms go together like bread and butter. Or, as Forrest Gump said, like peas and carrots. Only a fly fisherman might scoff at the notion of worms going with fishing. But even fly fishermen can find themselves dealing with worms, sometimes without even knowing. This is because there are other ways worms can end up with fish besides being prey. Some worms grow on or inside the fish.

First things first: We’re not talking about earthworms so the fly guys can relax. These “worms” are fish parasites, some of which actually are worms and some of which are not. Some look worm-like, while others look more like smaller versions of the white grubs that you find among decaying vegetation around the yard.

Most are internal, but there are external fish parasites too. External parasites are pretty common on sharks and can appear as threads hanging from the trailing edges of the fins. Other species of fish can get external parasites too. I’ve seen them mostly on pelagic fish like billfish and sometimes larger mahi.

But most of the parasites we encounter with our local fish are internal parasites that grow inside the fish for at least some part of their life cycle. Internal parasites can live in the digestive tract of fish, like tapeworms, or can live in the muscle tissue. It’s the muscle-living parasites that most of us have seen when we fillet fish.

How many of you have had this gross experience? You’re all excited about the beautiful fish that you caught and deposited into the fish cooler. You get back to the dock and hoist your trophy onto the fish cleaning table, start your first cut behind the head of the fish, slice down it’s length, then flop that fillet over to reveal the meat that’s destined to feed your entire family (it was a big fish!).

But then you spot something curious. There is something in that meat, maybe a bunch of somethings. Little white stringy things an inch or two in length and about the diameter of a pencil lead are inside the meat. Maybe there are only a few of them or maybe there are a bunch, but there they are right in front of you. Now what?

No one is happy to discover worms in the fish they are hoping to eat. But the reality is that many parasites live in fish, and most fish have parasites. If you have eaten fish more than once or twice, odds are you have unknowingly eaten some of these parasites in the meat.

But don’t rush off to the ER just yet. If the fish was solidly frozen before preparation, then any parasites were most likely dead. If the meat was thoroughly cooked, then any parasites are most definitely dead. Besides, most parasites that live in the flesh of a fish can’t survive in the hostile, acidic conditions of your digestive system anyway. If these things were not true, then there would be a bunch of fish-eating people at the hospital every day.

On the other hand, I know all of these things, and I still don’t like eating parasites in my fish. So I make it a point to trim them out of fillets as best I can, even though I sometimes end up losing a bit of meat. If you hold the fillet up to the sky, you can see the backlighted worms pretty well, though I know that I miss some of them. I will confess that, on a few occasions, I have tossed out a really infested fillet. Sometimes the fillet from one side of a fish will be full of parasites, while the fillet from the other side of that same fish will have none.

Fish can also have internal parasites in their digestive tracts, and so can humans for that matter. And some of the digestive tract parasites that are found in fish can do business in human digestive tracts if they can somehow get in there. The main way to avoid this potentially nasty situation is to avoid eating raw fish guts.

Do you eat a lot of raw fish guts? Neither do I. But do you remember way back in the day when college kids were swallowing live goldfish? That is an example of a good way to get pretty sick from parasites found in the goldfish digestive systems, and some of those kids developed serious issues. The copious amount of beer that was consumed along with the goldfish didn’t help. So don’t eat your leftover live bait, no matter how bad the fishing was.

It is interesting that some species of fish are much more prone to parasites in the meat than are other species, including some that you’d think might be similarly affected. For example, most of the red grouper we clean have at least a few parasites in the fillets, but gags almost never do. I have seen a few grublike parasites in redfish (red drum) but this is pretty rare. But black drum, especially fish over about 10 pounds, are likely to have worms in the meat.

Many of the spotted trout we fillet have worms in the meat, but silver trout (sand sea trout) almost never do. I cannot recall ever seeing parasites in the meat of snook or mangrove snapper or sheepshead, though I’m sure it’s possible.

There’s probably no need to quit eating fish because some fish contain parasites. As mentioned above, if you’ve eaten much fish, you’ve most likely already unknowingly eaten some parasites. The same is true of beef or other meats (and especially wild game and fowl) because parasites are quite common.

Before you decide to avoid this by turning vegetarian, let me ask you this: Have you ever taken a really close look at a clump of broccoli that came from your garden?

Capt. Ralph Allen runs the King Fisher Fleet of sightseeing and fishing charter boats located at Fishermen’s Village in Punta Gorda. He is an award-winning outdoor writer and photographer, and is a past president of the Florida Outdoor Writers Association. Contact him at 941-639-2628 or

Capt. Ralph Allen runs the King Fisher Fleet of sightseeing and fishing charter boats located at Fishermen’s Village in Punta Gorda. He is an award-winning outdoor writer and photographer, and is a past president of the Florida Outdoor Writers Association. Contact him at 941-639-2628 or


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