How Long Can a Betta Fish Go Without Food?

How Long Can a Betta Fish Go Without Food?

Feeding your fish is a vital aspect of caring for your fish. People often wonder how much they should feed their fish, what to feed their fish, and how to feed their fish while they are on vacation. Just like humans, people often underestimate how long fish can go without food. Humans, on average, can survive for nearly a month without food, but how long can fish go without food?

If your fish is being fed an appropriate amount and an appropriate diet, it will easily be able to go one week without food. Two weeks is pushing the boundaries, but it is not impossible. For most fish 10-15 days will be the maximum that they can go without food, but there will be some variation from fish to fish.

In this article, we will cover betta nutrition, vacation feeders, ammonia, vacation tips, and fatty foods.

Betta Nutrition

Bettas are rarely picky eaters and they will eat most foods offered to them. This can lead to an issue, as they will eat things that are very bad for them.

For example, there was an awful misconception circulating around about bettas and vases. Essentially, people would keep bettas in tiny, uncycled vases and not even feed them. This was because they believed that the betta would eat the plant roots and the plant roots would keep the water clean.

Unfortunately, this is woefully inaccurate. Terrestrial plants that have roots grow in water can improve water quality, but in a small container like a vase, they would never be able to take out enough ammonia or nitrite to keep the fish safe.

Of course, these bettas often did not live long, and people began to conclude that bettas only live for 1-6 months, instead of the actual 3-5 years that bettas do live. These bettas most likely died from several compounded issues, primarily ammonia and nitrite poisoning, but also bloat and swim bladder disorder.

The bloat and swim bladder disorder would have arisen if the betta was starved to the point that it attempted to eat the plant roots. Aside from the fact that most household plants are toxic to animals, bettas are not designed to eat plant matter.

Bettas are carnivorous, and just as a cat or dog cannot survive on plant matter alone, bettas cannot either. In addition, the domesticated betta is prone to bloat and swim bladder disorder if fed an improper diet.

By giving your betta too much plant matter, it will likely become constipated, and the blocked intestines can cause issues in other organs, such as the swim bladder. Bettas need to eat meat-based protein, not plant based protein.

Vacation feeders

Vacation feeders are white blocks that contain food inside of them. They are designed to slowly dissolve over time and release the food into the water, which the fish can then eat. However, these blocks very often do much more harm than good.

The food within the block is a very low-quality food and often nonspecific. This means it normally contains a lot of fillers, and just like dog and cat food, these fillers are normally plant based. Therefore, bettas cannot eat food from these blocks and remain healthy.

The blocks dissolve at varying rates, and there is not a standardized rate that they dissolve at. This means you may get one that you throw in for two weeks and doesn’t dissolve at all (I’ve had several of these failed ones) or you may get one that dissolves in a single day and released 20-50 pellets.

If your betta eats 20 pellets of food in a single day, it will probably die. I’m sure you’ve heard the expression “eat ‘till you pop”, but in this case, it is a little more literal. The betta will not pop, but it’s stomach will swell, and given that it will have a hard time digesting the food, the blockage will displace other organs.

The swim bladder will probably be the first organ to be affected, and your betta will either begin to sink or float and will be unable to maneuver properly. This condition would continue for quite a while due to severe constipation.


In addition to the feeder blocks containing food that is improper for a betta’s diet, they are also notorious for releasing large amounts of ammonia. Ammonia is the first step in the aquarium nitrogen cycle and is highly toxic to fish.

Even if your tank is perfectly cycled, these feeder blocks release so much ammonia that your beneficial bacterial will be unable to convert it to nitrite and nitrate quickly. This means you will also experience a severe nitrite spike in your aquarium in the following week.

Therefore, if you are away on vacation and unable to test your tank or change your water, the outcome is not good. Ammonia causes problems on the outside of the fish, mainly chemical burns.

The main issue is that ammonia causes severe and potentially permanent damage to the gills, which can reduce your fish’s lifespan. It will also burn off scales and fins and can severely harm the eyes and mouth.

Nitrite is sneakier. The only external symptom will be your fish gasping at the top of the tank blowing bubbles. However, your fish may also start to develop a red belly, but at this point, the damage that has been done is often too severe to recover from.

Nitrite causes what is commonly referred to as “brown blood disease”. It is not a disease, but rather a symptom of nitrite poisoning. It got its name from the fact that the blood of severely affected fish can turn brown.

Nitrite binds to hemoglobin in the blood and prevents the blood from carrying oxygen through the body. Without oxygen flowing through the blood, the fish will begin to suffocate.

Vacation tips

Automatic feeders are a better alternative to vacation feeder blocks because you can control the amount of food released each day. Although there are several reports of them malfunctioning and releasing extra food, they are safer than the blocks.

On the other hand, if you are only going to be gone for 10 days or less, it is perfectly fine to leave your fish without any food. In fact, this is the safest option. Whether or not you are going to use an automatic feeder or no feeder at all, you should prepare for your vacation in the same way.

For 3-4 days before your trip, you should start preparing the tank. Do a large water change of 50% on the fourth day before you leave. Starting either that same day or the next day, slightly increase the amount of food you give your betta. Instead of feeding your fish twice a day, feed it three or four times a day, but feed 1.5 times as much food overall. For example, if you normally feed two pellets in one day, feed 3 instead.

Splitting the extra food into extra feedings should give your betta enough time to digest that food before its next meal. Be cautious, and if you are in doubt, feed less. You don’t want your betta getting bloat or a swim bladder disorder while you are gone.

On the last day before you leave, feed your betta a normal amount of food. Wait at least two hours after your betta’s last meal of the day, then do a large 50% to 70% water change. Since nitrates will build up while you are gone, you want to reduce them as low as possible before you go.

Fatty foods

The normal rule of thumb about feeding your betta fatty foods is to only feed them one to two times a week. These foods should not be plant based, but rather something like white worms or bloodworms.

However, you can increase the feedings of these right before you go on vacation to raise your fish’s fat stores. You should still only give 2-3 meals in the 4 days before you leave to prevent bloat. This may seem like a very small increase, but bettas are very small fish, and it does not take a lot of food to build fat reserves.

In conclusion, betta fish can easily go one week without food and suffer no ill consequences. Some can even go two weeks without food if you prepare them properly. If you go on vacation, there are several easy ways to ensure your fish makes it through that time period, even without food.

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