How much does a betta fish weigh?

In this article, we will answer the question “How much does a betta fish weigh?”. We will also discuss the betta fish size and some overweight topics.

How much does a betta fish weigh?

A maturing betta fish can weigh at least 3 grams to 3.5 grams, especially if it is healthy, however, a newborn betta or betta fry weighs just approximately 0.02 to 0.05 grams. The fish can acquire weight as it gets older and larger, eventually weighing around 3-4 grams or more. Male and female betta fish have different weights.

What is the betta fish size?

A betta fish’s usual length is 1.9-2.25 inches, but some betta fish can reach 3 to 4 inches in length if they live and thrive in a healthy environment. The longest betta fish ever reported is roughly 6 inches long, which is unusual. 

One of the most fascinating fish you may encounter is the betta fish. These little fish can be grown in containers, fish tanks, or even in open water. 

It’s fine to be curious about the length of a betta fish when we’re talking about its weight. And, just so you know, the places or environments in which kids grow, as well as the food they eat, have an impact on their health and development. 

Bettas, on the other hand, grow to a specific size before becoming fully formed adults. But how long do they take to mature?

  • One Day Old: Only a few hours ago, the betta fry emerged from the egg. It will be between 0.01 and 0.02 inches long. At this point, the tail will not be visible.
  • One Week Old: The betta fish will be roughly 0.03 inches long after its second week.
  • Two Weeks Old: The betta’s length will be around 0.25 inches. Other portions of the body, like the dorsal fins, will begin to show signs of growth.
  • Three Weeks Old: By the third week, the betta fish will be 0.35 inches long.
  • Four Weeks Old: When the betta reaches a month of age, its typical length will be 0.45 to 0.5 inches.
  • Five Weeks Old: At this stage, a betta fish’s typical length is around 0.6 inches. Some of them, though, can grow to be 0.7-0.75 inches long.
  • Six Weeks Old: A betta fish that is six weeks old will be 0.85-1 inch long. Only the largest bettas reach 1 inch in length at this stage.
  • Seven To Ten Weeks Old: Between six and ten weeks, you will notice that the betta fish is looking good and more in its full form. Between now and then, the length will increase from 1.1 to 1.8 inches.
  • Eleven Weeks Old: By this time, a betta fish has grown to its average size. It will be between 1.9 and 2 inches tall.

The betta will continue to grow after this stage until it reaches adulthood. A betta reaches adulthood between the ages of six months and one year. 

The actual age varies from betta to betta, therefore it’s impossible to say. However, when fully grown, the betta will be at least 2.25 inches long and up to 4 inches long.

Can a betta fish get fat?

Betta fish can acquire obesity for a variety of reasons, which may surprise you. It could be because the betta has a voracious appetite or because of what you’re feeding it. 

Obesity in fish is not as uncommon as you may imagine. Let’s look at some of the reasons why betta fish gain weight.

Low activity level

Obesity is a common problem among captive bettas. While bettas in the wild are more active and can move around in a large space, bettas in fish tanks, especially small ones, have limited movement room. Lack of space causes the betta to be less active, resulting in obesity.

Too much food

You must be careful about what you feed the betta fish. Overfeeding your pet can lead to excessive weight gain, as much as you like treating them with more food and treats. It’s advisable to stick to a feeding schedule that specifies how many times you’ll feed the fish and how much food you’ll provide each time. 

Keep in mind that the sort of food the betta consumes has an impact on its weight gain. The best thing you can do is feed it betta fish food. Leave enough food for the fish to finish in under a minute. A few modest snacks now and then would also be fine.

How to tell a betta fish is overweight?

Looking at your betta from the top or a dorsoventral position is the easiest way to see if it’s overweight. The betta is overweight if its head and shoulder appear to be of different forms, or if its tummy appears to be large and protruding in the centre. 

It’s not difficult to spot a fat or overweight betta fish, just as it is with an overweight cat or dog. To tell the difference, it all boils down to their central body part. Fish have the same girth at the head and shoulder, and their internal body parts start at the head and extend to the last third of their body. 

The head and shoulder will appear to be the same length if the betta has a healthy body. 

If the betta is overweight or overfed, though, you’ll notice that its head and shoulder are different lengths and shapes. The betta is overweight if its belly bulges and extends beyond its girth.

What will happen if a betta fish is too fat?

Constipation and prolapse are two problems that might occur if the betta fish grows obese or overweight. Constipation causes lethargy and may be treated, however, a betta fish suffering from prolapse has a reduced chance of survival. 

Constipation is one of the most prevalent health issues that bettas exhibit as a result of overfeeding or weight increase. And if you don’t take care of this problem, it can lead to more serious illnesses. If the betta appears to be constipated, you can either leave it unfed for two to three days or feed it frozen daphnia. 

In betta, prolapse is the most serious side effect of constipation. The organs begin to tumble out of place as the betta bloats. 

Because the betta is such a small fish, surgery to correct the problem is not an option. To end its misery, the only and kindest thing you can do is euthanize it.

How to make my betta fish lose weight?

The best technique to shed weight in a betta fish is to adjust its eating habits or reduce the amount of food you feed it each mealtime. The betta’s diet chart should only have enough protein and fat, and the food pellet you feed should be exactly right. 

Uncontrolled feeding or feeding the betta high-protein, high-fat foods causes it to gain weight. And, as you’ve already learned, it might put your prized fish’s life in jeopardy. As a concerned owner, the right thing to do is to assist it in losing weight. 

It’s fine to feed fat and protein-rich foods to your betta fish. However, it is your responsibility to ensure that the amount of food given to your fish is not excessive. You can switch to a different food brand if you suspect a certain type of food is causing the betta to gain weight. 

Then there’s the food pellet you’re feeding it. Reduce the number of feed pellets fed to the betta. If you do this for a few weeks, your betta will begin to lose weight. Also, mix up your diet now and then. Pellets aren’t always the best option. Bettas enjoy periodic treats such as bloodworms, mealworms, freeze-dried shrimp, brine shrimp, and so forth.


In this article, we answered the question “How much does a betta fish weigh?”. We also discussed the betta fish size and some overweight topics.

If you have any thoughts or doubts, feel free to drop us a comment below!

Frequently Asked Questions (FAQs): How much does a betta fish weigh?

How big do bettas get?

Betta fish normally grow to be no more than 4 inches long. Their average lifespan is between 2 and 5 years. They have brightly coloured fins and a variety of tails.

What kills betta fish?

A poor habitat, such as unclean water, an ill-kept tank, unsuitable fish, a tank that is too small, and other factors, is the most prevalent cause of mortality in Betta fish. Betta fish are prone to stress, so it’s crucial to limit their exposure to it and keep an eye on how they react to new situations.

Do betta fish get bored?

If you keep your betta in a small tank with no decorations and give it the same food every day with no variation in its surroundings, it will become bored quickly. And boredom is a common cause of sadness and stress.

Do betta fish like to hide?

Bettas prefer to swim alone and require a secure hiding spot. Aquatic tunnels or densely vegetated corners are excellent places to make a betta feel secure. 

Are mirrors good for betta fish?

Using a mirror isn’t detrimental to your betta, but using it excessively can be. While your betta will be stressed when it sees its reflection, it will be a healthy tension. And as long as you don’t overdo it to the point where it becomes fatigued or frantic, it won’t harm you.

Do betta fish like light? 

Yes, anything too bright can irritate them, but a basic aquarium light would suffice. Bettas also enjoy aquarium plants, which require aquarium lighting to thrive.


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