How Big Do Betta Fish Grow? How Do I Make Sure They Grow Larger?

Hey Pet Parents & Pet Lovers,

I’m very important to know how big your animals are going to get, especially if they are animals that need to be caged or in tanks. While you may assume that the smaller the animal, the smaller the cage/enclosure needs to be, this isn’t always true. For example for Betta Fish, you’re going to want to make sure your tank is at least 2-gallons, although 5-gallons is the common recommendation if you want the best for your Betta.

Wait, 5-Gallons? Why so large? How Big Do Bettas Grow?

Bettas actually average out at 2.25 inches long, however, that doesn’t mean that these beautiful fish don’t need a lot of space.

What’s the largest a Betta Fish has gotten?

Betta fish have been known to get as large as 3 inches.

Is a Betta Cube appropriate for a Betta Fish?

Sadly, no they are not appropriate for Bettas. So, why do pet stores supply them? Well, while Bettas are able to survive in tanks this small, it doesn’t mean that it doesn’t stress them out. Betta Cubes are fairly easy to take care of and are “a great way” to learn how to take care of fish.

What are the problems with small tanks?

Well, like you, fish need exercise. The bigger the tank, the more space they are going to have to swim around and make sure they are fit. Smaller tanks also get dirty fairly quickly, especially because they commonly don’t have carbon filters. Due to this, the ammonia and other filth will build up very quickly. Betta Cubes require you to do a 100% water change at least twice a week.

So, what you’re trying to say is I’m just going to be cleaning more?

No, smaller fish tanks actually have more negative effects on your fish than you may realize and can actually have a negative impact on their health!

What negative impacts on my fish’s health can a small tank have?

Well, your Betta might not actually grow if you leave them in a small tank. There’s evidence that proves that bettas who are kept in smaller tanks will not grow to their full size to accommodate their tanks. This means that if a tank is too small your betta will grow to around 1.5-2 inches in length. Although this is the case you can actually manipulate your Betta’s environment to help encourage them to grow larger. If this is something that is important to you or something you are interested in, you’re going to want to make sure that you have a tank that is large enough to support the growth of your Betta Fish.

Okay, Okay! Before you tell me, why is it pet stores have Bettas in small cups?

Well, this is for the primary purpose of making sure that they don’t get territorial with each other. Betta cups don’t provide enough space for them to fight with each other (or become territorial) and are often made with glossed/fogged sides so the Bettas don’t have a chance to see each other. This makes it easy and safe for pet stores to store and house bettas, however, the hope is to get them adopted quickly.

So, if the pet stores can do it and do a good job at it, why can’t I!?

Something you’re not going to hear from pet stores is how often these fish get sick in their small containers. The pet store I used to work at used to house Bettas, and I would say we’d have at least one fish pass away a week. The bettas would most commonly pass on from getting ick, fin rot, or stress/shock. While there are tons of medications like Ampicillin, MELAFIX, tetracycline, or erythromycin that can help with these problems, a young betta who gets sick has a lower chance of living longer. The sicker they get in the fish store, the shorter their life expectancy gets.

So how do I make sure my Betta grows up big and strong?

Make sure your Betta is in a suitably sized tank. If you need help selecting a tank to check out our top tanks here.

Keep the temperature between 72-80°F. This will make sure that your Betta is nice and warm and too cold to grow larger. (We use Marina’s Compact Heater)

Change half of the water on a daily basis. The easiest way to explain this is by saying that Bettas produce a hormone that makes them stop growing. Always make sure that you replace the water with preconditioned water (or use water conditioner) and bacteria to make sure that the Betta doesn’t get shocked.

Make sure your betta is getting a lot of protein and fibre. Live foods can help make sure that your betta is getting enough nutrients. If you’re interested in the different types of feed check out my article here!

Make sure your Betta is Happy!