Does Fish Food Expire? What Every Owner Should Know

Charlie Morton

Charlie Morton


Does Fish Food Expire

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Every kind of fish food has some sort of expiry date that comes with it. While you may be able to use dried products a little past their use-by date, it’s important to avoid using seriously old fish foods, especially if they show any signs of decay.

There are different rules for storing each kind of fish food and some clever ways to make them last longer. Let’s take a closer look at them here.

Expiry of Dried Fish Foods

Dried fish foods are the most popular type; one reason is that they last a long time. The most common types of dried food are flakes, pellets, and freeze-dried fish food.

How Long Do Fish Flakes Last?

Flake foods in bulk normally come with an official shelf life of 18 months to 3 years. But in a sealed container, they may easily exceed their shelf life.

Flake foods are normally dried to just 10% of their original weight and are sealed with foil to create an airtight package that makes them store very well until opened, just like human food. 

Once opened, however, flake foods are exposed to oxygen and moisture, which can begin to degrade their quality.

The large surface area of flakes means they can become soggy and oxidate relatively quickly.

I used to notice that when my container of flake food was about half empty after a month or so, I’d start to notice it feeling a little bit less crisp than a fresh pack.

But this was partly because I used to keep the container on top of the tank, which is definitely not the best place!

As water from a heated aquarium evaporates, it creates a warm, moist atmosphere around and especially above it – not the ideal environment for things staying fresh!

In general, flake foods are best kept in a cool, dark place and tightly sealed between feeding to help them last as long as possible.

How Long Do Pellet Fish Foods Last?

Fish pellets are a bit more robust than flakes in their longevity. According to fish food manufacturers, they’ll show very little deterioration in a sealed container and tend to last three years or so. 

Once open, they’ll not absorb water or oxygen as fast as flake foods but should still be stored carefully. Otherwise, your fish will get fish food poisoning. 

The storage of pellets depends on their size, nutritional composition, and how many preservatives have been added.

Fish pellets are typically made up of varying quantities of fish meal, shrimp meal, spirulina, and some vitamins and minerals. Some fish pellets contain fillers such as wheat, corn, soy, and other types of fish food.

The vitamin C tablets and content in dried fish food, such as pellets, can help them last longer by providing an antioxidant effect while also nourishing your fish with this essential vitamin.

How Long Do Freeze-Dried Fish Foods Last?

Supplementary freeze-dried foods like Daphnia, garlic extract, Hikari wheat germ, Bloodworm, Hikari Saki, and Tubifex last the longest out of any kind of dried food. The expiry dates on these packets can be up to 15 or 20 years!

This is because freeze-drying squeezes 98% of the moisture from fresh food (as opposed to 90% in regular drying), which makes it last in a sealed container or plastic bag almost indefinitely. Once opened, though, freeze-dried foods should be used within six months.

Remember that freeze-dried foods should only be fed as a supplement rather than at every feeding time, so a small pack should last your fish quite a long time.

How Long After The Expiration Date Can I Use Dried Fish Food?

In a sealed container, dried foods like fish flakes and pellets may last up to three months after their use-by date.

Be warned, though, that with time, the nutrient content of your dried fish foods will diminish. While bone-dry food is unlikely to be dangerous to your fish, it won’t be as nourishing for them as it once was.

If you’re using fish food close to or just past the expiry date written on the packet, consider supplementing your fish with extra helpings of live or frozen foods. This will ensure they get all the vitamins and minerals needed to remain in optimum health.

How Long Can I Use Dried Fish Food After Opening It?

Generally, it’s a good idea to use dried fish foods like flakes, pellets, and freeze-dried foods within 6 months of opening the container.

As soon as your packet of fish food has been opened, oxygen and moisture from the air can enter and begin to degrade your product.

Does Fish Food Expire

After a few months, you may notice the food isn’t quite as crisp or fresh-smelling as it once was.

If your fish food becomes soggy, foul smelling, or has any sign of insect life in it, it’s definitely best to throw it away.

How Can I Make My Dried Fish Food Last Longer?

Store It in a Cool, Dark Environment

You can extend the life of your fish food by keeping it in a cool dark place, away from any sources of moisture. This applies to fish food that’s been opened and food that is still sealed. It also applies to dried and freeze-dried fish food. 

As well as water and oxygen, light and warmth also play a role in degrading your fish food. If you keep your packs of fish food well-sealed in a cool, dry, darkened closet, they’ll have a better chance of lasting longer.

Freeze Any Food That You Won’t Use Within a Few Months

Since economic food cans of dry fish food often come in larger quantities, some fishkeepers like to empty a portion of the packet straight into ziplock bags for freezing.

That way, they can feed the first part of the pack to their fish while it’s still fresh, knowing that the remaining food is almost as good as new in the freezer!

If you’d like to try this method, seal your food bags thoroughly, as any moisture entering your dried foods will cause them to rot very quickly once thawed.

Buy Top Quality Fish Food

Commercial fish foods vary enormously in their quality and packaging.

For the longest shelf life, opt for vacuum-packed foods, nitrogen-packed, or that come in cans. At the very minimum, there must be an airtight seal on the bag or container in which you buy your fish food.

Expiry of Frozen Fish Foods

Frozen fish foods like Bloodworm, Brine Shrimp, and Mysis Shrimp have an expiry date of around six months.

If they’re kept permanently frozen, they might last longer than this – but it’s better not to take the risk! These meaty foods can easily spoil and become toxic for your fish.

When feeding frozen foods, you also need to understand how long they’ll last once thawed. It’s normally advised to thaw frozen foods before feeding so that your fish can eat food in a more natural state.

But, alas, it’s not always easy to remember to feed that block of bloodworms we thoughtfully put on a dish to thaw a few hours ago! Many of us were greeted the next day by a foul stench from our kitchen!

If your frozen food has been left out for more than 12 hours, it’s probably best to throw it away.

If there is any kind of bad smell coming from it, bacterial decomposition has started, and it could be dangerous to your fish.

Expiry of Live Fish Foods

If you enjoy feeding your fish live foods like brine shrimp, vinegar eels, or mosquito larvae, you don’t need to worry about the expiry date in the conventional sense. But let’s not forget that every living thing has its expiry date too!

Keeping your live foods in optimum condition is essential to remain a healthy snack for your fish.

If you purchase them from a store, make sure they come from a reputable source and that the water they are swimming in is clean and clear.

Check to see if all the little critters look healthy and full of life.

If any of your live foods start to die, discard them rather than feed them to your fish.

In the warm environments, they are raised in, bacterial infections can take hold very quickly, and you don’t want to feed infected foods to your fish!

Tips and Tricks For Managing Frozen Fish Foods Safely

Frozen foods can be good for your fish, and most of us should feed them more often. They’re closer to the natural diet of your fish than dried foods, and they also come loaded with high-quality proteins, healthy fatty acids, vitamins, and essential minerals.

Sadly they can seem less convenient than dried foods, though. We’re often too lazy to go to the freezer, pop out some frozen cubes and wait all that time for them to thaw. But it doesn’t have to be that way.

By taking out five days’ worth of frozen foods from the freezer at a time and keeping it in the fridge, we can easily and safely feed the thawed food to our fish every day.

If you’d like to try this method, just keep the thawed food in a tightly sealed container or bag in the fridge to help it stay fresh. Discard anything that’s left after five days.

Another method is to use a frozen fish food dispenser in your aquarium. This clever kit lets you put frozen food blocks directly into your tank and lets the dispenser do the thawing and feeding for you.

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Can I Use Silica Gel Packs To Preserve My Fish Food?

You may have noticed that some brands of fish food come with a silica gel pack inside to help preserve the contents.

Silica is great for keeping dried foods fresh because it absorbs excess moisture, acting as a desiccant for anything that shares its container.

So, by all means, keep the silica gel in your store-bought fish food container to help continue its preservative effect.

And if you are making your own dried food, you can also buy silica gel packs to help keep it fresh.

A little goes a long way, though: One sachet for up to one pound of fish food should be plenty.

How Long Does It Take for Goldfish or Koi Fish Food To Expire?

Just like other fish foods, goldfish food and koi pellets have a limited shelf-life too. These pellets are often larger than typical aquarium pellets and may last a bit longer.

You could probably continue feeding your goldfish or koi carp these types of pellets for up to one year after opening the packet, so long as you keep it tightly sealed in the ideal storage conditions we’ve spoken about.

How Long Does It Take for Betta Fish Food To Expire?

Betta pellets are specially formulated to contain high protein levels and float well to match the feeding preferences of Betta splendens; the Siamese fighter fish.

Like other fish pellets, betta pellets last up to three years in an unopened container but need to be used within six months of opening.

This can present a challenge for the betta keeper because bettas are often kept alone and don’t need much food!

If you have a single betta fish, it’d be a great idea to use the freezer method! Take half of the betta pellets from the container and place them in a tightly sealed bag or box in the freezer so that you’ll have another batch of fresh food to feed your betta fish in six months.

Is Old Fish Food Dangerous to My Fish?

If it becomes rotten or infected, expired fish food could poison your fish. This is less likely to happen with dried foods, but frozen foods can start to decompose quite rapidly once they’re thawed.

But a more likely cause of poisoning to your fish is the food left at the bottom of the tank uneaten!

No matter how fresh it is, if fish food goes uneaten, it will quickly decay in your fish tank and release toxic ammonia into the water.

Poisoning from overfeeding is a bigger killer of aquarium fish than poisoning from expired foods, so always be sure to feed no more than your fish can consume within a few minutes.


Like all perishable goods, every kind of fish food has a limited shelf life. Whether you’re feeding your fish dried, frozen or live foods, you need to ensure that they’re fresh and in good condition.

It’s always best to throw away any foods that may have turned rancid rather than risk your fish’s health. But with some know-how, you can safely preserve your fish food so you won’t have to waste any.

Check out our full guide here to learn more about safe and effective fish feeding.

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