How to Breed Axolotls

It's true:

Axolotl maturity during breeding is critical.

This begs the question:

"How old does an axolotl have to be to breed?"

Males are pretty straightforward.

They can hit sexual maturity as early as 6 months (though 8 months is more common).

(They also don't usually get as large as females.)

When the male is ready, his cloaca will be large and he will appear to have stopped growing.

[Read More: How to Tell Your Axolotl's Gender]

What about females?

There are those who like to have a hard-fast rule of no mating females before 18 months...

... But honestly, this is more of a blanket statement that does not take into consideration things experienced breeders judge whether or not a female is fit to breed.

For example, an 18 month old female may well be at breeding age, but she may still not be in the proper condition to breed.

The way I see it?

A more accurate rule of thumb would be that females should be in peak physical condition and totally finished growing before mating.

She should be at least 8" and have been properly conditioned - in excellent health and ideally with a full, plump belly.

(Some females are just naturally thinner than others though.)

The reason?

Depending on husbandry, some axolotls can reach a suitable breeding age sooner than others.

In fact...

MOST females are full grown well before 18 months.

Here's my opinion:

Time is not necessarily as important as size and stage of life.

An axolotl's growth and the point at which it reaches maturity depend more heavily on environmental conditions such as food and available space.

When well fed, some axolotls can hit adult size in a rather short timeframe.

(Interestingly enough, this is the case for many other aquatic species as well, not just axolotls.)

For this reason, some hit breeding age sooner than others - sometimes even sooner than 12 months.

Males can mate a bit sooner, as it is not as hard on their bodies.

Some people give the 18th month rule for breeding females to help prevent them from being bred prematurely, as some owners do not feed heavily or bother doing any sort of conditioning and thus the female matures much slower and is at a greater risk for being overexerted through the breeding process.

This bears repeating:

If she's not done growing, it's not safe to breed.

Experienced axolotl breeders can and do breed sooner than 18 months in some cases, but they must know what to look for.

If you're not sure, or if it's your first time, it's not a bad idea to wait.

When in doubt... wait until you're totally sure she's done growing and is in prime condition, be it 18 months or more.

Choosing Stock

Choosing your breeding stock is important.

Any male and female axolotl may breed, but without the proper understanding of genetic backgrounds, you may end up without much if any of the more in-demand morphs.

Do the potential parents have matching hets, or do they share homozygous traits?

If not, the clutch will likely be all or mostly wilds.

Finding homes for these can be a challenge and come at a high expense, sometimes resulting just in breaking even on the expense invested into breeding and raising the animals.

Seemingly healthy axolotls that have come from a clutch with a higher than normal instance of deformities should not be bred, as severe inbreeding is a possibility and they can pass on these problematic genes.

Setup Requirements

A quick preface:

Breeding is not for the faint of heart.

It requires money, time and space.

You will need at a minimum a conditioning tank for the males, a conditioning tank for the females, a spawning tank, and grow-out tanks to raise the larvae.

You will also need an outlet to find homes for all the babies.

Separating by sex is important.

Males and females generally breed better when kept apart in totally separate environments.

(Tank dividers still allow the animals to see and smell one another.)

Not only does it ensure you can pair the exact animals when you are ready that you want to breed...

... It keeps them from breeding prematurely.

The conditioning tanks should be outfitted with the following:

• Proper filtration and aeration
• Hides
• Live or fake plants

More water volume is better, as during the conditioning period you will need to feed heavily. Smaller tanks get dirty faster.

For lack of tanks, large plastic tubs or even baby pools can be substituted.

Try to ensure 10-20 gallons per axolotl for conditioning tanks, although the spawning tank can be a bit smaller (a 15 or 20 gallon tank filled 2/3 full is sufficient).

When do Axolotls Breed?

They breed when they want to, and not a minute sooner.

The breeding season is generally December through June for axolotls - once right around the days before the shortest day of the year, and once in the spring.

A couple of days after a low pressure front often triggers spawning behavior.

These are good times to plan your introductions.

Hotter months like August are often the least successful times.

That said:

Axolotls may breed at any time of the year, if conditions are favorable.

They may also breed when conditions are not favorable.

Bottom line?

It's their timetable... not ours.

The decision rests with them.

We breeders can only try to convince them ;)

If they don't want to breed, they won't, sometimes no matter what you try.

Usually it's the female who is the roadblock.

Sometimes a female just doesn't take to a male you want her to be with.

If that's the case, sometimes the only way is to try another male...

... and another...

... Until you find the one she is pleased with.

Pre-breeding Cooldown

Not all axolotls require a cool-down period.

But some are more stubborn than others, and if you really want to ensure success, this is a trick you can use.

It also seems to help the female develop greater quantities of eggs.

A colder period of 4-6 weeks helps the animals to go into a hibernation-type "winter mode."

A cool basement or garage is perfect for this.

Some people use a refrigerator for this, but I'd generally recommend against this as it's more stressful.

I aim for temperatures between 40-50 degrees F. Sometimes it gets into the high 30's.

The axolotls must be adjusted to this colder range slowly over the course of several days or it can cause shock.

Also:

Darkness is important.

Shorter light cycles during this period help to signal to the animal that it is winter, time to snuggle down.

During this hibernation period, they will eat less. This is normal.

Feed when they want to eat, and remove uneaten food.

Conditioning the Pair

After 4-6 weeks go by, the temperature and lighting should gradually start to increase again, signaling to the animals that spring is here.

Naturally, their appetites will increase.

Now:

It's time to ramp up feeding.

Feed the animals heavily - as much as they want to eat 1-2x per day, high quality, high protein foods.

Live earthworms and marine-based protein sources are the best foods to feed for conditioning in my experience.

You should start to see the females filling out in their abdominal region, whereas males cloaca become more pronounced as they are put into breeding condition.

All of this feeding can lead to dirty water, so be sure to keep the bottom well cleaned and the water in tip-top shape.

Tip:

Doing water changes with cooler water helps to mimic spring rains and snow melt.

When the female is looking really wide and full of eggs, she is getting close to being ready to breed.

Males may drop spermatophores in their tank even without the presence of the female as they too become conditioned.

Preparing the First Meeting: The Spawning Tank

First, you must set the mood. :)

Ideally, the tank should be placed in a private area without much foot traffic or light.

If the tank is opaque, it's not a bad idea to block one or more sides by draping dark fabric or even a piece of wood next to it (on the outside of course).

Now:

The spawning tank should be outfitted with an abundance of soft plants (plastic or live) and flat stones on the bottom.

The plants will be a spawning site for the female to lay her eggs, and the stones will be a place for the male to deposit his spermatophores.

Males CAN breed without the stones, but the rougher surface helps the spermatophore stay in the proper position.

Current should be minimized - the use of a cycled sponge filter is ideal to afford oxygen and clean water (which can help promote breeding) to the newly laid eggs, helping to prevent fungus.

It may be better to keep the water a bit shallower than normal.

Ideally, after being properly conditioned, the water should be aged for at least 42 hours.

Ice can be added to the tank if it is a bit warmer than what the conditioning tanks were set at - aim for a temp between 64-68 degrees F.

Axolotl Pairing

Introducing the pair before midday is useful, that way you can observe what is happening and interfere when needed.

Try not to disturb them during this process or they could get distracted!

1. Add both the male and female into the tank. They may begin to spawn as soon as 1 hour or the next day.
2. If spawning is likely, the male will be the one to initiate. He will start wiggling his tail, nudging the female and laying spermatophores here and there. His gills will often turn bright red and his tail bright pink, especially if he is lighter in color.
3. If the female is receptive (which may take her a while to decide), she will accept his advances and then begin to participate in the mating dance by curiously following him around, picking up the spermatophores with her back feet and absorbing them into her cloaca.
4. The male will continue to chase the female around, trying to show her where he put the spermatophore so she can pick it up. She usually won't pick them all up during this time. This process lasts around an hour.

Once the pair is done, the male should be removed to give the female some privacy to lay (and so he won't eat all those tasty eggs!).

Any lingering spermatophores can be left in place for the female to absorb that night.

Here's the exciting part:

Between 3 hours to 3 days after spawning, the female will start to lay eggs.

The egg laying process for female axolotls takes 1-2 days to complete.

During this time, she will get busy crawling all over the plants in the tank and laying her eggs one by one - anywhere between 100 and 1000 eggs.

Once she's done laying, she should be removed so she doesn't eat all the eggs.

Fun Fact:

You can do a "double pairing" of 2 females to 1 male if you wish to test the genetics at one go.

Be warned - you will probably have a TON of eggs!