What To Do If Your Axolotls Accidentally Breed

Introduction

Many axolotl owners run into the problem of going to check on their axolotls one day and finding hundreds of eggs in the tank! They had no idea their axolotls were even opposite sex because maybe they got them before they were sexually mature, or were unaware of what to look out for in order to identify the sex of their axolotls. But, what do you do when this happens? In this article we will discuss the options available to axolotl owners if their axolotls ever accidentally breed.

Pictured above: axolotl eggs

First Things First, Separate the Parents

Now that you know for sure your axolotl’s are opposite sex, they need to be permanently separated from each other, because a male axolotl can breed a female axolotl to death. Setting up a new tank is the best solution, but if you are unable to do so, then it might be necessary to rehome one of the parents.

Pictured above: an axolotl spermatophore (photo credit: Mikeg from caudata.org)

Some people recommend using a tank divider, but you need to be careful of which one you try, because some of these products are not 100% effective due to the fact that axolotls do not breed the same way that mammals do. Male axolotls actually lay their sperm (called spermatophores) on the ground and the females pick it up with their cloaca and inseminate themselves. Because most dividers need to have plenty of holes and spaces for water to flow freely, spermatophores can inadvertently find their way to the female, allowing breeding to occur, even if the male axolotl never touches the female. The best way to utilize a divider is to have one that is completely solid with no holes or gaps. You will need a separate filtration system for each side of the divider.

Ask The Important Questions

Axolotls are an extremely inbred species. Especially in captivity. Even if your axolotls come from two different breeders, they could still be related as it is extremely common for breeders to purchase from and trade with one another. Why is this an issue? Well, axolotls that are inbred tend to be homozygous for recessive genes that drastically affect the axolotl’s development and health. It would be incredibly sad, and unethical, to raise or sell axolotls that are doomed to live short and possibly painful lives. Even if these babies are not at risk of being inbred, raising axolotls from eggs is extremely time consuming, potentially costly, and difficult for those who are just starting out. There are some serious questions you need to ask yourself in order to determine the best course of action.

Did your axolotls come from the same breeder around the same time?

If the answer to this is yes, then there is a very high chance that your axolotls are related, as it is 100% possible for a single clutch of axolotls to have a multitude of morphs. Your axolotls don't need to be the same morph to potentially be siblings. In this instance we strongly recommend contacting the breeder to confirm if the axolotls are related or not. If they are, then the best course of action is culling the eggs, as releasing possibly hundreds of inbred axolotls to the already shallow gene pool will further hurt the species as a whole.

Do you know what the genetics of your axolotls are?

By genetics, we mean the genotype, sometimes referred to as hets, of your axolotls. If you choose to keep these eggs, it’s important to know what kind of babies will be produced. Consider reaching out to the breeder to inquire about the hets of your axolotls. If your axolotls don’t have any matching hets, 100% of the babies will be Wild Types, and Wild Types are notoriously much harder to find homes for than other morphs of axolotls, even if you are giving them away for free. You don’t want to find yourself in a situation where you have more axolotls than you can realistically care for.

Are you willing and able to dedicate a large portion of your time and money to raising these babies?

Breeding and raising axolotls is a full-time obligation. Hatchlings in particular are much more labor intensive than any other life stage. They need their own tubs or tanks, daily water changes, and frequent feedings every single day, otherwise they will cannibalize each other. All of the necessary supplies for rearing axolotls will also cost you quite a bit of money if you don’t already have them on hand. Hatchling axolotls also have very specific dietary requirements that can be difficult to cultivate or expensive to purchase. The time necessary to dedicate to this endeavor also means you will not be able to take a day off for several months while tending to these babies.

Will you be able to find homes for all the babies if you decide to raise them?

Axolotls can lay up to a thousand eggs. Unless you have a very large space, and a multitude of tanks available, it’s simply not realistic to assume you will be keeping every single baby forever. You’ll most likely need to rehome or sell them. Are you confident that you will be able to find homes for all the babies? Many people find it difficult, even when giving them away for free. Will you also be able to provide adequate support and care instructions to the people who want to buy your axolotls, but have never owned one before?

How To Ethically Cull Eggs

If it’s even remotely possible that your axolotl eggs are inbred, or you simply do not have the time, space, knowledge or funds available to raise any of the babies, then the best course of action is to cull the eggs. Even if you do want to try your hand at raising some of the axolotls, you will still need to cull excess eggs. We strongly recommend only keeping about 10 eggs if you want to try breeding for the first time. The purpose of this is to avoid instances of mass neglect or abandonment of these animals, which usually leads to a prolonged and painful existence for them. Similar instances have happened in places like New Zealand, where animal rescues are being completely overwhelmed by thousands of abandoned axolotls from owners who didn’t know what to do when their axolotls accidentally bred.

Axolotls have evolved to lay so many eggs because, in reality, only one or two of their offspring will actually make it to adulthood in the wild. Laying up to a thousand eggs is an evolutionary strategy to, at minimum, guarantee the replacement of the parents in regards to population numbers. In captivity this is not the case. There are no natural predators to eat the eggs and future larvae, or adverse environmental factors preventing development of the embryos. So, overpopulation of tanks, neglect, disfigurement from constant nipping, and the spread of deadly diseases can easily happen to the animals of an axolotl owner who refuses to responsibly cull excess eggs. Culling eggs before they have a chance to develop is significantly less cruel than allowing them to hatch, only to then realize that you can’t adequately care for them.

Instructions

1. Gather the eggs using either a large turkey baster or very gently with your hands.
2. Place the eggs in a ziploc bag.
3. Put the bag into your freezer for 72 hrs.

• This is the best way to stop the development of the embryos. As long as you cull the eggs before they are allowed to fully develop, they will feel no pain.
• After 72 hrs has passed you may dispose of the frozen eggs into the trash or compost.

Alternative Options

If you find yourself unable to cull the eggs, but also know that you can’t care for the offspring, there are some other possibilities for you.

Selling the Eggs

Many people sell their axolotl eggs in online forums, to local fish stores, and to schools or universities. You need to be willing and able to safely ship the embryos to whoever you sell/donate them to. Here is a guide on shipping salamander eggs and larva. As with anything, it’s best to research the prices other people sell their axolotl eggs at and price yours accordingly. If your axolotl eggs are potentially inbred, you must make that known to anyone interested in these eggs. Including the hets and possible morphs of your eggs will also increase the chances of someone being interested in them.

Donate the Eggs to a Local Breeder or Herpetological Society

If you aren’t able to cull the eggs, a local breeder or herpetological society may do it for you, or be willing to rear the eggs and find them homes if there is no risk of inbreeding. Someone who already has the infrastructure and knowledge to raise the eggs can be an easier solution than trying to rear them all by yourself. Please be as transparent about the parentage and genetics of these eggs as much as possible as many breeders rely heavily on their reputation and most would rather do the ethical thing with inbred eggs than accidentally raise and sell axolotls that could potentially die prematurely.

Important Note on Releasing Axolotls as an Alternative to Culling

Never, under any circumstance, release your axolotls or axolotl eggs into the wild. Captive bred animals can be more prone to diseases and illnesses that wild populations are not. If these diseases are released into the wild, it can cause extreme harm to wild populations. Diseases like Batrachochytrium dendrobatidis are directly responsible for the extinction of multiple amphibian species. This deadly parasitic fungus can easily transfer to captive bred animals via feeder fish and then to wild populations if the infected animal is released.

The animals will die if they cannot adapt to surviving in the wild. This would almost assuredly be a death sentence for the released animals. Even experienced and knowledgeable biologists who attempt to release captive bred reptiles and amphibians experience consistent failure in their released animals being able to adapt to wildlife.

It is illegal to release non-native captive bred animals into any area.

Conclusion

Responsible husbandry of critically endangered animals, like the axolotl, requires not just thinking about what is best for the animals you have, but for what is best for the species as a whole. It’s important to be able to make these difficult decisions from as informed of a position as possible. We hope that this information helps you to make the right decision for yourself and the animals under your care!