How Big do Axolotls Grow?

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The axolotl sizes can vary greatly. Sometimes, they are preconditioned and cannot be altered, while in other cases, you can impact on how much the axolotl will grow. But still, there is a set growth parameter that is set within the genetic material of an individual axolotl.

How big do axolotls grow?

The sizes can vary. The normal sizes of axolotls are between 15-25 cm (6-10 inches). These sizes are just the average, and some can grow larger, while others will be smaller. The size depends on several factors that we will go through later on. The axolotl will usually complete its growth cycle when it’s 2 years of age. After that, there is little to no space for growth.

In this article, we’ll take a look at why axolotls can stop growing, and how you can boost their growth.

Common Reasons Why Axolotls Stop Growing

There are various reasons for this; sure, the size is usually defined by genetics, although that’s not always the case. Sometimes, it can be impacted by external variables, and many owners don’t even know that they control these variables. So you can boost their growth, but the growth is limited.

These are the most common reasons why axolotls will stop growing.

Aquarium Size

The number one reason why axolotls stop growing is aquarium size. When the aquarium is too small for an axolotl, it might be limiting their growth hugely. If it has nowhere to move, not enough space to live properly, the axolotl will adjust to the tank size and will stop its growth.

If you don’t want this happen to your axolotl, you should consider the minimum requirement that an axolotl needs to grow fully. That’s 10 gallons of water in an aquarium, and it’s preferred to have even more than that, if you can. If the tank is too small, the axolotl will not have enough space to grow and will adapt.

Water Parameters

You might not know it, but water parameters can control how much an axolotl will grow. Ideal water parameters will give the axolotl a better chance of growing, while wrong parameters are one of the reasons why they won’t grow more.

For example, excess ammonia will prevent the growth. Having no ammonia is optimal, and it will encourage better growth. Similarly, water temperatures can massively impact the growth. Too warm or too cold water can stunt the growth. Other parameters that can impact the growth are PH levels, and other properties.


Sometimes, it’s just impossible to impact how much your axolotl will grow. The growth is set in stone and written in the axolotl’s genetics. Even if we try to impact the growth, there’s some set values of how much they can grow, regardless of the conditions.

Some axolotls will naturally be smaller, and others will be larger. It’s like with every other being out there.


Food is an important piece of axolotl’s growth cycle. We’re talking about the quality of the food, as well as the type of foods we feed them. The higher the quality of the food, the more the axolotl is likely to grow. That’s why it’s always better to buy higher quality foods, regardless of the type we feed them.

We should avoid bad foods at all costs, as well as feeding the axolotl just one type of food. In fact, variety is perhaps even more important than the quality. When we feed the axolotl only one type of food for years, we are sure to stunt their growth massively.

We shouldn’t only feed them pellets, for example, but we should supplement them with live or frozen dried foods. In any case, the foods we give them should have quality nutrients that are needed for growth – proteins, a good amount of healthy fats, as well as carbs.

Crowded Tank

If you have an overcrowded tank, then that might be the reason for your axolotl not growing. It’s a similar concept to having a tank that is too small. If there are too many fish or axolotls together, then your axolotls will not have enough space to evolve completely and grow as much as it can.

So make sure you don’t cramp everything into one small aquarium. You should give every animal more than enough space to live normally, grow as much as they can. As the poor axie will have nowhere to grow, it’ll stunt its growth and you won’t see what the full growth potential of your axolotl is.

How to Speed Up Baby Axolotl Growth Rate?

You should try to increase and improve the growth rate of an axolotl while they are young. Starting as soon as possible is essential, but knowing how to increase their growth rate is just as important. Here are some of the best things you can try to increase their growth rate.

Offer Them Enough Space

Yes, giving your axolotl enough space is the first thing you should do. Even if the axolotl is still a baby axolotl, you should give them enough space; prepare as if they were fully grown axolotls, because one day, it will become a fully grown animal. And if you have multiple baby axolotls, that’s even more important.

As the axolotl will adapt to the tank size, you should provide them enough space to enable them to grow as much as they can. Equally, you should not cramp too many animals together in a small space, as it can also decrease their growth rate massively.

Keep Water Parameters Optimal

Now this tip should not only be incorporated to increase the growth, but it should be considered at all times. You should always try to keep optimal water parameters, no matter what. And these are even more important when you want to grow your baby axolotls as much as you can.

Keep the temperature in check, clear the ammonia in the water, and have a good quality of filtration in order to get rid of all the harmful particles in the water. So the best idea is to always have the water parameters at optimal levels.

Offer Good Variety & High-Quality Foods

Food is a crucial aspect that determines how healthy the axolotl will be, and how much it’ll grow. So you should offer a good variety of foods, but more importantly, the foods should be of a high quality standard. Avoid cheap foods just because of the price; instead, consider good quality foods, and buy various food sources. Live foods, frozen dried foods, as well as pellets can be considered in combination.

Separate Baby Axolotls by Size (as they grow)

As the axolotls grow, they will limit each other and take each other’s space. So when they grow, it might be a wise idea to invest into another tank to keep the grown axolotls separately.


Axolotls can grow to between 15-25 cm (6-10 inches). The sizes can vary, and it turns out that in some cases, we can impact the growth. But we have to start when the axolotl is still young; it includes having good water parameters, feeding them quality foods, and giving them enough space to grow. If your goal is to grow the axolotls as much as you can, then you should follow these tips.

Updated: September 1, 2022

Questions & Answers

  1. Hi, just curious about what to do when it’s time for a filter change? Do I need to be worried about them not having the bacteria they need in a new filter?


    1. avatar
      Axolotl Nerd

      If you want to change the filter on your tank, you should now just do a swipe, because all the beneficial bacteria from the old filter, which was supporting the ecosystem will be gone.
      You should install your new filter, and let both filters run for about 1-2 weeks, so the filter media in the new filter will be fully colonized with beneficial bacteria. After that, you can remove the old filter, but still monitor the water parameters for a few days to see if the new filter is doing its job well enough.

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