How long can a Fish stay in a Bag? (8 Considerations to Know!)

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Written By Fun Fish Tanks

I Love my Fishes 

Seeing a fish in a bag is not an unusual sight. Even if you are new to this hobby, you must’ve seen people carrying fish in a bag. You will bring your new fish home in a plastic bag as well.

You might be thinking it is alright and the fish is alright in a bag, but fish cannot remain in a bag for a long period. A bag is not the ideal environment for the fish, it doesn’t have enough space, and you can forget about water parameters.

The amount of time that fish can stay in a bag depends upon various factors. But regardless of anything, a fish must not remain in a bag for long.

In this article, we will go through how long a fish can remain in a bag and other questions regarding keeping fish in a bag. 

How long can a fish stay in a bag? 

If you’ve ever seen fish kept in a bag, you’ve probably wondered how long they can survive in a bag.

A fish may survive in a bag for 8 to 10 hours. Many pet stores or aquarium stores will add extra oxygen to the bag, allowing the fish to survive for up to 48 hours.

The amount of oxygen in the bag has a significant influence on the fish’s life. However, this does not imply that you should leave your fish in a bag for as long as it can survive.

It is best for both you and your fish if you leave your fish in the bag for 5 to 7 hours.

8 Considerations When Keeping Fish in Bags 

8 Considerations When Keeping Fish in Bags 

One day or another, a circumstance arises in which you must keep your fish in a bag for an extended period. When adding fish in a bag, you must run over some considerations.

1. Instead of atmospheric air, fill the bag with oxygen

If you must keep your fish in a bag, such as when traveling, you must fill the bag with oxygen rather than air.

It is fine filling your fish bag with air for short periods, such as an hour. Your fish is unlikely to suffer from asphyxia at that period. 

If you must travel for several hours, it is best to add oxygen to the bag to prevent the fish from suffocating.

To keep your fish safe in a fish bag, the oxygen should occupy up to two-thirds of the bag.

If the appropriate conditions are met, this can keep your fish alive for hours or perhaps a day or two. You should not, however, travel with your fish in a bag for more than 5 to 7 hours. 

2. One fish in one bag

Only one fish may be kept in a single bag. The higher the number of fish in a bag, the oxygen use rate increases.

However, if the bag is large enough and the fish are little enough, you can keep more than one in a single bag. However, not for a lengthy time.

For larger fishes, choose a proper size bag and retain only one in a single bag. If you’re going to be gone for an extended amount of time, keep one fish in a single container.

If you bought a few fish and the retailer gave them to you in one bag, you should hurry home as soon as possible.

3. Don’t let the bag sit

Though fish may produce water flow in the bag by swimming in it, this allows oxygen to enter the water.

Some fish may perish if the container remains stationary. Water movement allows oxygen from the atmosphere to enter the water, allowing the fish to breathe.

Make some water movement by moving the container from time to time to allow oxygen to flow in the water.

4. Keep fish in a big bag

If you intend to keep fish in a bag, make sure the bag is large enough. A bigger bag means more space for air or oxygen. The extra oxygen in a larger bag permits a fish to stay in the bag for a longer time.

The fish may also absorb more oxygen from the surface of the water. It removes the need to continuously open the bag to replenish the oxygen content.

You should also avoid filling the bag with too much water. It won’t leave much room for oxygen or air. Only one-third of the volume of the bag should be filled with water. If you fill the bag largely with water, there will be insufficient space for air or oxygen, and your fish will perish.

5. Maintain a comfortable temperature

If you’re transporting fish in a bag, you must maintain the surrounding temperature as cool as possible.

Keep the temperature temperate whether you’re traveling or bringing fish home from the market.

Fish can handle normal temperatures, but if the outside temperature is high or cold, the temperature of the water in the bag will change often.

When paired with adverse outside temps, this can injure and even kill your fish. If the weather is unusually hot, consider taking a trip in an air-conditioned vehicle to keep the temperature under control.

To keep the water temperature stable, you can use either cold or hot packs. Just don’t allow the cold weather to alter the water in the bag.

6. Avoid and manage ammonia buildup

Before leaving, you must not feed the fish for a day. Because the fish will be kept in a bag if they produce waste, ammonia will quickly accumulate.

Fish can survive without food for up to a week, so you don’t have to worry about them being hungry. Excess ammonia can be harmful to fish, although it is unusual for it to become life-threatening.

Ammonia buildup can also be minimized by keeping the water temperature low. Allowing the water to become too cold may also cause complications for your fish.

7. When traveling, don’t keep the fish in the bag for too long.

Try to keep the fish in the sack for the shortest length of time feasible. Make the fish the last thing you pack while traveling or relocating to a new house.

Also, after you get to your location, the fish should be the first thing you take out of the bag. Remember to bring a big bag with shallow water and fill it with oxygen instead of atmospheric air.

8. What will happen if you keep fish in a bag for too long? 

A fish in a bag for too long is bad news. Keeping a fish in a bag for too long is not good, they will suffocate if they are in a bag for long. However, it occurs when the oxygen within the bag runs out.

As previously stated, a fish may survive in a bag filled with atmospheric air for around 8 to 10 hours.

However, avoid storing it in a bag for an extended time. You should also avoid adding too much water to the bag since more water results in less air within the bag.

If you’re going anywhere, it’s advisable to fill the bag with oxygen rather than air to ensure the fish’s life. However, when the oxygen levels drop, the fish will perish.


So fishes can stay in a bag for 8 to 10 hours. But you must not keep a fish in a bag for more than 7 hours. If the bag has oxygen in it, the time to keep fish in a bag can extend.

Aquarium stores usually add oxygen to the bag to allow fish to stay longer in a bag. Although you might not wish to keep a fish in a bag, there will come instances such as travelling where you are compelled to keep fish in a bag.

Although you have to keep the time you keep fish in a bag as minimum as possible. If you keep it in a bag for too long it will suffocate. 

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