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“Ask a Vet” is on pause

I’ll be honest… I’ve been receiving way more questions than I can handle, and I need a little break! Here are some resources you can use in the meantime:

• If you’re in the Montréal area, contact Royal Vet and ask for an appointment with Dr. Goldenberg
• To consult a veterinarian online, try
• For community advice, check out Axolotl & More Canada on Facebook or MeWe

I wish I had the time and resources to keep offering free help to everyone who needs it, but that’s simply unrealistic given the number of emails I receive every day. I’m burnt out, and I’m not sure how I’m supposed to pay my bills at this point. Thank you for understanding, and I’m sorry if your email is one of the ones that fell through the cracks.


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Axolotl skin growths

What should you do if your axolotl suddenly sprouts some kind of mass? Here’s a flowchart to help you navigate through the lumps and bumps.

Axolotl skin growth flowchart

Are you having difficulty finding a vet for your axolotl? Your local cat and dog vet should be able to refer you. If you’re in my area (Montréal, QC), email me for a recommendation. In Canada and the US, you can also try online services such as fishvet or vetster.

Are you a vet willing to treat axolotls? Email me so I can help you get the word out, and connect you to other vets with axolotl experience.

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Why I don’t recommend keeping guppies with your axolotl

Yes, I know they sound like a good match in theory. Guppies are typically considered beginner fish, they’re not super nippy, and they reproduce a lot. Even if your axolotl eats a few, you wouldn’t miss them. Plus they like cooler water than most tropical fish, they can handle the water hardness and just like your axolotl, and they wouldn’t mind a bit of salt.

So what’s the problem, exactly?

The guppies you see in pet stores mainly come from Southeast Asia. A lot of them are grown outdoors, in cage farm systems. The water is on the warmer end of the range guppies can tolerate, and usually brackish, if not full saltwater. Because of the open environment, the fish are exposed to pathogens and parasites that can be transmitted to your axolotl.

Asc1733, CC BY-SA 4.0, via Wikimedia Commons

This photo shows a wealthier cage farm operation — I’m guessing they’re raising tilapia in there, and the guy on the boat is a company employee, not an independent farmer. Guppy farms tend to be cooperative affairs, with smaller, crowded cages and shoddier installations. Remember, these are being farmed in poorer countries, generally by people who struggle to make ends meet. I’ve watched a presentation from a Thai government official, explaining that guppy farming is such an important part of the economy over there, the government is scrambling to educate farmers about basic sanitation. One common issue they face is contaminated fish food. Contaminated fish food. Being introduced into open bodies of water. Because the farmers are struggling financially, and the fish food directly cuts into their profits, so they’ll use any old crap the fish are likely to eat, even if some of it has been made illegal. Because these are poor people with families to feed, not greedy corporations. They make the least money of anyone involved in this production chain. They are not educated about fish health, or the ecological impacts of what they’re doing.

Of course some of the fish die. It’s not easy to spot and remove them in these kinds of setups. They just get eaten by the herd. And then some more fish die at every step of the process that ensues, which is the government’s main concern. Waste of money, you know?

Here’s what the process looks like: the fish get collected by individual farmers, and dropped of at a transit station. Then they travel some more to get to a larger sorting station, where the fish get separated by sex and colour. Then they’re sent to the transhipper, who organizes the international sales. From there, they’re bagged, sent off to customs, and once they’re cleared for travel, they get shipped overseas. They land in some airport, where they have to clear customs again, and then they’re put on a delivery truck.

By the time they arrive at the wholesaler’s, the fish are hungry and stressed out, and basically not in any condition to withstand sharing their water with a bunch of other random species who have just gone through similar ordeals. But they get put into aquariums that are all connected together anyway, because individual water changes would be a logistical nightmare, and way too time-consuming. The wholesalers would lose money.

So of course, some more fish die. But guppies are hardy, so most make it out okay — enough for the wholesaler to make a profit. Not a lot of profit, but enough to stay in business. Guppies don’t sell for much, but every pet store buys them in large quantities, so they’re pretty much guaranteed to sell out every week.

This means the fish don’t get to stay at the wholesaler’s for long. The sick ones get put down, and the healthy-looking ones get shipped to individual pet stores, where they may or may not get quarantined, or treated with “preventive” medications (often antibiotics, but not the full course, because that would be too expensive.) Then they get displayed along with other fish species. Most pet stores use inline water recirculation systems similar to wholesalers’, because that makes water changes easier and cheaper. So these fish are separated by species, but they’re all passing pathogens back and forth.

Then you come in and buy the fish. You take them home, and let’s be honest, you probably don’t quarantine them, because you don’t have a spare aquarium with a cycled filter, right? Most people don’t. Heck, I’ve skipped quarantine before. (Have I regretted it? Oh yeah.)

But let’s say you’re a smart cookie. Keeping all of the above in mind, you decide to quarantine. You have a nice tank set up just for your new guppies. No heater. Maybe a little salt. And they seem fine! You’re not seeing any signs of illness or any icky worms sticking out of their butts. So after a couple weeks, you add them to your axolotl tank. There’s a sudden increase in the bioload, because you’re adding the new fish all at once, but your axolotl is already a big nitrogen producer, so the ecosystem adjusts.

Here’s the thing. Your axolotl is most comfortable in water that’s somewhere between 16 and 18°C, but can handle higher temperatures, with stress and illness occuring at 22°C and above. Despite what you may have read online, your guppies are most comfortable between 23 and 24°C (references here and here.) They can handle lower temperatures, with stress and illness occuring at 18°C and below (reference here). This means the range at which the two species can comfortably coexist is between 19° and 21°C. That’s not a lot of leeway.

So you aim for a steady 20°C, right? It’s doable, with the right equipment. Except these guppies probably grew up in 26-28°C saltwater, during which time they were exposed to all sorts of pathogens, and they’ve been under a lot of stress for the past one or two months. Asking them to suddenly adapt to cold freshwater is a lot. Listen, I used to live in Florida. It was sweltering hot over there! Then I moved to Canada in the middle of winter. I was sick for two months, and I got frostbite.

And sure, despite all of that, guppies are still a hardy, beginner-friendly fish. Chances are they’ll survive, and unless you’re an experienced fishkeeper, you may not even notice that they were upset for a while. But that’s part of the problem. Because you know who’s not a hardy beginner animal? Your axolotl. Who may or may be eating sick, parasite-infested guppies. This is why I keep saying that the guppy-axolotl combo is best left to experienced aquarists. You need to be able to spot the subtle cues that let you know when something isn’t quite right. You need to be prepared to intervene quickly, you need to know how to treat the most common guppy health issues, and you need to know how to treat your axolotl, too.

“But wait, what if I buy those really expensive guppy strains with carefully selected fin shapes and colour patterns? Surely those weren’t cage farmed and fed contaminated crap?”

You’re right, these fancier strains come from facilities that are often much cleaner, with tightly controlled water parameters, appropriate food, and regular health checks. The problem is, in order to meet the strain’s beauty standards, these fish have to be line bred for several generations. It’s tricky, and more importantly expensive, to line breed in a way that won’t weaken the fish genetically. So while they may leave the facility in peak health conditions, these fish still end up exposed to a lot of the same pathogens as the less carefully raised fish, because they share the same water at the transshipper’s place, then at the wholesaler’s, and then at the pet store. And since the fancier fish are weaker genetically, and never really got the chance to build up strong immune systems by virtue of being raised in clean environments, they are even more likely to get sick than those hardy cage-raised mutts.

Does this mean you have to give up on guppies? Of course not. As people point out to me all the time, the internet is full of axolotl-guppy success stories. How do these people manage it?

The key is to choose guppies who were born and raised in the type of water your axolotl enjoys. How do you find those? Ask around! Some fish stores buy fish from local breeders. Online classifieds are full of people trying to get rid of their extra guppy fry. Most cities have aquarium societies, where fish breeders meet up to share knowledge and hold auctions. Choose a fish that grew up in your water. They’ll be much more likely to stay healthy, and so will your axolotl.

And hey, if all else fails? Get those guppies from the pet store, but give them their own aquarium. Make it comfortable for them, with some salt and the kind of temperatures they prefer. Then once they have babies, move those in with your axolotl. It will be much less of a shock for these second-generation guppies, going from their native environment of 23°C with a tablespoon of aquarium salt, to a 20°C tank with only one teaspoon. And you won’t need to add all of the fish at once, which means your bacteria will find it much easier to adjust.

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Are axolotls legal to own/breed/sell in Canada?

Updated Feb. 12, 2023

In some Canadian provinces, a permit is required to own axolotls, breed them, sell them, and import them from other provinces. Additionally, due to their status as an endangered species, axolotls require a CITES permit to import axolotls in or out of the country. Finally, no matter where you live, it’s your responsibility to make sure you comply with your city by-laws regarding pet ownership and pet breeding.

As of 2022, there is no limit on the number of axolotls you can keep as pets without a permit. You are also allowed to breed, sell, and rehome your axolotl. You are allowed to import axolotls from other Canadian provinces without an official notice, but only as an individual importing a personal pet.  Axolotl owners and retailers have certain legal obligations, which I will detail in another article.
Source: C-61.1, r. 5.1 – Regulation respecting animals in captivity (Aug. 1st, 2022)

ON, MB, SK, AB, NL, NT, YU and NU
To the best of my knowledge, no permit is required to own axolotls as pets in these provinces and territories. My information could be outdated, so I plan on going through the text law over the next few weeks. In the meantime, if you plan on adopting an axolotl, I recommend contacting your local wildlife department to double-check.

If you live in one of these provinces, you are not allowed to own or import axolotls without a valid permit from your local wildlife department. I strongly urge you to comply with these regulations — axolotls get seized from their owners all the time. It’s quite a traumatic experience, both for the owners and the animals. Pet stores also face expensive fines.

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Adopt an Axolotl or Newt

Are you ready for a 15 year committment?

Axolotls and Spanish ribbed newts can live as long as a cat or a dog. Like any other animal, they can get sick or injured and may require veterinary care at some point. If you are an parent getting a pet for a child, are you prepared to look after the animal yourself if needed? If you are a student, will you still be able to care for your pet if your workload increases or your living situation changes?

Who can apply?

  • Adult residents and facilities located in the following Canadian provinces and territories: ON, QC, MB, SK, AB, NL, NT, YU and NU
  • Educational, research and wildlife conservation facilities in any Canadian province, with the appropriate permits from your local wildlife department where required (NB, NS, BC, PEI)

Note that we cannot ship to rural areas. If there’s a zero in your postal code, you must be prepared to come pick up your axolotl in Montréal, QC or Calgary, AB.

Is your aquarium ready?

Before submitting this form, please familiarize yourself with the Nitrogen Cycle and basic care requirements. We will not sell you an animal unless you have the appropriate housing setup for it, including a fully cycled filter.

Adoption Application for Water Critters and Hollies Hobbies Calgary

If you can’t see the adoption form below, try turning off your ad blocker or use this link to access the form directly.

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How to Tub Your Axolotl

The proper way to tub your axolotl depends on what you are trying to accomplish. There are several reasons why you might want to tub your axolotl:

  • To house your axolotl while your tank is cycling
  • To hold your axolotl during water changes, feeding and/or emergencies
  • To treat a sick/injured axolotl
  • To transport an axolotl during a move or a trip to the vet
  • To house growing larvae or juveniles
  • To house a special-needs axolotl permanently

I’m going to cover the first point right now, since that’s the information most people need in a hurry, and I’ll come back and edit the rest in later when I’m in less of a hurry. (Oh, the joys of running your own business!) But first, here’s a quick list of food-grade plastics — you’ll need to refer to it when choosing a housing container for your axolotl.

Plastics considered food-safe in Canada

  • Plastic #1 (PETE)
  • Plastic #2 (HDPE)
  • Plastic #4 (LDPE)
  • Plastic #5 (PP)

How to tub your axolotl while your tank is cycling

You will need:

  • two food-safe plastic totes, large enough for your axolotl to move around comfortably
  • at least one piece of floating decor, to provide shade and prevent jumping (anything reminiscent of a lily pad is appreciated!)
  • water conditioner, if your tap water is treated with chlorine/chloramine
  • a turkey baster (choose one with a wide opening if possible)
  • a thermometer
  • a soft sponge (nothing that could scratch plastic)

Follow these steps once a day:

  1. Fill up a clean, dry plastic container with cold tap water (enough to cover your axolotl by at least 2 inches). Add water conditioner if needed.
  2. Remove any decor and set aside.
  3. Use the turkey baster to remove any axolotl poop. Dump it right into your aquarium! It will keep your bacteria fed and help the cycling process.
  4. Feed your axolotl before transferring it to the new clean tub.
  5. Once your axolotl is done eating and both tubs are roughly the same temperature (±2°C), transfer your axolotl.
  6. Use the soft sponge and hot water to clean the decor. Rinse with cold water, then add to the clean tub.
  7. Dump out the dirty water. Use the soft sponge and hot water to clean the tub. Let it air dry.

Other tubbing scenarios coming soon! If you need help with tubbing in the meantime, feel free to email me. For cycling help, check out these articles: Introduction to the Nitrogen Cycle and How to Cycle Your Aquarium.

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COVID-19 Announcement

As many of you know, I have been away for the past few weeks due to health issues (unrelated to the current virus crisis). First, I’d like to thank you for your patience, concern and well-wishes. I’m doing much better!

The government of Quebec has recently announced the closure of all non-essential services. Thankfully, pet stores are considered essential, so I will be returning to work on March 31st as planned. For the foreseeable future, I will not be holding regular store hours, but will be conducting business online or by appointment. You may contact me via email, Facebook, or call/text 514-882-2758.

Important note regarding shipping of live animals:
Due to the current self-quarantine measures adopted throughout the country, there has been a major increase in online purchases of all kinds, causing extreme delays for all regular shipping providers. For the time being, all live animal shipments will be conducted through Reptile Express, a specialized shipping service which guarantees delivery times and live arrival. Since my shopping cart application is not equipped to live estimate this company’s shipping rates, you will need to contact me to obtain a personalized quote. Thank you for your understanding!

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Axolotl Socialization Tips

Axolotl socialization
My giant boys, Pixel and L, sharing a polite axolotl greeting.

Tip #1: Most axolotls will have grown out of their cannibal phase by the time they reach a full body size of 3.5 to 4 inches. Make sure to pair axolotls which are similar in size. Cannibal phase or not, if one’s head can fit inside the other’s, it will be considered food!

Tip #2: Choose a time when both axolotls seem relaxed, healthy and have a full belly. It’s very important to feed them well beforehand!

Tip #3: A protein-deficient axolotl is likely to bite tankmates, regardless of age, relative size and other circumstances. So make sure you’re feeding an appropriate diet, and if your axolotl is a rescue, give them a couple weeks of adequate nutrition before introducing them to your other lotls.

Tip #4: Supervise the first interaction and get ready to separate if needed. Getting in each other’s space is okay. Sniffing each other is okay. Being a little jumpy is normal too. Fast stomping towards the other with the nose down to the ground is a bite waiting to happen, so get ready to intervene. Snapping right in front of each other’s face is more of a threat, but still a sign that the axolotl isn’t ready to accept a tankmate. Separate and try again in a few weeks.

Tip #5: If all goes well for the first few minutes, supervise at feeding time for the first several days. That’s usually when aggressive behavior comes out. Try to feed in separate areas of the tank so that they aren’t tempted to go for each other’s food. Stealing food from each other’s mouths is a no-no, as it encourages bites on both sides. Snapping close to each other’s limbs is also not good, so try not to let the food end up close to someone’s toes. Feed the more food-aggressive axolotls first, then feed the more timid ones at a safe distance from the more voracious ones.

Tip #6: If you notice that one axolotl tends to hide a lot, won’t come out at feeding time, and turns away from food, they are either feeling sick or are scared of a food-aggressive tankmate. Separate and try again once both animals seem happy and healthy.

Tip #7: If a pair doesn’t get along right away, don’t get discouraged. Separate them and try again in a few weeks. Just because it didn’t go well last time doesn’t mean it won’t work out next time. Axolotls live in the moment, they don’t hold grudges. I promise!

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Axolotl Genetics, Part 3: Melanism and Axanthicism

In part 2 of this article, we went over albinism, a recessive genetic mutation which affects one type of pigment cells (melanophores, responsible for the dark pigment eumelanin). As you can easily guess, there are also mutations which affect the other two types of pigment cells: iridophores, which produce shiny white crystallized purines, and xanthophores, which produce yellow pteridines. In this section, we will focus on these two mutations, which are a bit more complex than albinism.


Melanism is a recessive mutation similar to albinism, but instead of affecting melanophores, the mutation acts on iridophores. All axolotls receive either the M or m allele from each parent, which means their genotype for the melanism trait is either:

  • M/M (homozygous dominant)
  • M/m (heterozygous)
  • m/m (homozygous recessive)

Homozygous dominant and heterozygous axolotls develop normal iridophores, which means they are able to produce crystallized purines (the shiny white pigment). Homozygous recessive axolotls are called melanoids. Since they have no iridophores, they are unable to produce cystallized purines.

This mutation also has a spillover effect: the lack of iridophores triggers the conversion of some xanthophores into melanophores. This is why melanoid axolotls show more eumelanin (black) than any other color morph, and almost no pteridines (yellow). This gives them a grey appearance, which can border on blueish under the right wavelengths.

Due to the reduced number of pteridines, which are important to immune function, melanoid axolotl larvae have a slightly lower survival rate than wild-type or albino axolotls. This is why melanoid axolotls they tend to be a bit more expensive and slightly less common on the market than other color morphs.

The lower amount of pteridines makes melanoid axolotls appear almost blue under certain wavelengths. Here is X, one of my melanoids, under blue and white LED lights.

This melanoid axolotl has just a hint of yellow pigment on his face, which gives him an almost wild-type look. We can tell that he is a melanoid because his eye ring lacks the metallic shine of wild-type axolotls. Photo by Patricia’s Gill Babies.

This axolotl is both melanoid and albino, which means it has a lower than normal amount of xanthophores (caused by melanism) in addition to a complete absence of melanophores (caused by albinism). This explains why so few yellow pigments are visible on its skin. Photo by Samantha Nicole.


As you can imagine, axanthicism acts on xanthophores, the pigment cells responsible for producing pteridines. But the name of the trait, which means “lack of xanthophores”, is actually misleading. As it turns out, axanthic axolotls do have a certain amount of xanthophores, but those xanthophores are unable to produce pteridines due to a genetic mutation, which is believed to have originated from a virus.

Even though they can’t produce pteridines, the mutant xanthophores are able to store some yellow pigments from the axolotl’s diet (chiefly riboflavin, also known as vitamin B2). This helps compensate a bit for the lack of pteridines, but since they are slowly accumulated over time, axanthic larvae still have a low survival rate compared to other color morphs. This, along with the strict import laws currently in place, explains why axanthic axolotls are nearly impossible to find on the Canadian market.

In addition to causing a complete lack of pteridines, the axanthic mutation prevents iridophores from differenciating during development. As a result, axanthic axolotls often look a lot like melanoids. One way to tell them apart is to look at them under a blueish light. The complete absence of yellow pigments at birth tends to give axanthic a purple hue, whereas melanoids are more of a blueish grey. The purple effect tends to fade over time due to the accumulation of other yellow pigments, but some axolotls (such as Sarah, below) do manage to retain it through adulthood.

To make matters more confusing, axolotls can be both axanthic and melanoid. If an axanthic axolotl is especially dark, chances are it is also melanoid, but there is no way to be certain unless the genotype of both parents is known. If an axanthic axolotl accumulates a lot of yellow pigment over the years, then it probably isn’t a melanoid, as melanism further reduces the overall number of xanthophores.

Sarah, showing the purple-grey color characteristic of axanthic axolotls. Photo by Leslee Anne Vanden Top (Axolotl Heaven).

Pale axanthic axolotls such as this one are sometimes called “lavender”. Despite looking similar to light melanoids, lavender axolotls are unlikely to possess the melanism trait. Photo by Leslee Anne Vanden Top (Axolotl Heaven).

Chances are this very dark axanthic male is also homozygous for melanism. Photo by Leslee Anne Vanden Top (Axolotl Heaven).

<- Axolotl Genetics, Part 2: Mendelian Inheritance and Albinism | Axolotl Genetics, Part 4: Leucism, Copper and GFP [Coming Soon!]