Everything You Need To Know About Axolotl Blue

The striking blue coloring of axolotls has fascinated aquarium hobbyists and scientists alike. If you’ve ever wondered why some axolotls are blue, you’ve come to the right place!

If you’re short on time, here’s a quick answer to your question: The blue coloration of axolotls is caused by a rare genetic mutation that results in a lack of iridophores in the skin, allowing the black melanin in the cells underneath to show through.

In this comprehensive guide, we’ll cover the genetics behind blue axolotls, how blue color morphs originated, their unique traits and care requirements, why blue axolotls are so rare, and much more.

The Genetics Behind Blue Axolotls

Melanophores and Iridophores

The beautiful blue color of blue axolotls is caused by two types of pigment cells in their skin called melanophores and iridophores. Melanophores contain melanin, which produces colors like black, brown, and gray.

Iridophores reflect light to produce shiny, iridescent colors like blue, green, and purple. The combination of these two pigments is what gives blue axolotls their distinctive blue hue.

Researchers found that blue axolotls have a mutation in a gene called SLC45A2 that causes them to produce more melanophores. These extra melanophores interact with the iridophores to create blue coloring.

Albino axolotls lack melanophores entirely, while wild-type axolotls have some melanophores, but not enough to appear blue.

The Blue Gene

The SLC45A2 gene responsible for blue coloration is fittingly nicknamed the “blue gene.” It codes for a protein that helps control melanin production and transport within melanophores. The mutated version found in blue axolotls confers blue coloration through a phenomenon called allelic mosaicism.

Allelic mosaicism is when an individual has two different versions of a gene. In this case, blue axolotls have one copy of the normal SLC45A2 gene and one copy of the mutated “blue” version. This results in a mosaic pattern of expression, with some cells making normal amounts of melanin while others make extra under the influence of the mutated gene.

Albino Axolotls vs Blue Axolotls

While blue axolotls have a mutation that increases melanin production, albino axolotls have a mutation that prevents melanin synthesis altogether. This results in a complete lack of color, making albino axolotls entirely white or translucent.

Here’s a quick comparison of some key differences:

While they look quite different, both variants originate from genetic mutations affecting melanin synthesis and transport. Axolotls are unique for having color mutations that are viable and can be propagated, allowing preservation of these striking but natural genetic variants.

The Origins of Blue Axolotls

Natural Occurrences

Blue is an extremely rare color variant that occurs naturally in the wild axolotl population at frequencies of less than 1%. The blue coloration comes from a genetic mutation that causes a lack of black pigment cells, resulting in the brilliant blue hue underneath.

Given the low chances of this mutation occurring, finding a blue axolotl in the wild is incredibly uncommon. There have only been a handful of documented cases over history. This strikes experts as astounding given that the axolotl is native solely to Lake Xochimilco in Mexico City.

Selective Breeding Efforts

The rarity and beauty of blue axolotls have made them coveted in the pet trade. Starting in the early 2000s, breeders began selectively reproducing axolotls expressing the blue color variant. By breeding blue axolotls with each other or with other colors showing the mutation, more blue offspring could be produced.

Through dedicated and careful selection over about 15 years, blue axolotls are now readily available, though they still command high prices due to popularity. Top-quality blues from championship bloodlines can cost $300 or more.

With increasing numbers, blue axolotls aren’t as rare as they once were but are no less magnificent.

Unique Traits of Blue Axolotls

Appearance

Blue axolotls have a striking, unique appearance that sets them apart from other axolotl color morphs. Their body is a pale blue or grayish hue, while their gills and frills are a vibrant azure blue. Their eyes are also blue, lacking the gold flecking seen in wild-type axolotls.

The combination of blue tones makes them look like exotic underwater creatures.

The blue color is caused by a mutation in pigmentation that prevents melanin from forming properly. This results in less black pigment overall, allowing the underlying blue hues to show through. Like albinos, blue axolotls lack dark colors but they retain some blue pigmentation.

Their blue skin is translucent, making their internal organs faintly visible. This gives them an otherworldly, ghostly look. Blue axolotls may glow under blacklight due to their pale skin and lack of pigment. They are truly one of the most unique looking axolotl morphs.

Behavior

Blue axolotls exhibit typical axolotl behavior. They are generally calm, peaceful creatures that spend most of their time resting on the bottom of the tank. Axolotls are not the most active pets, but blue axolotls can be slightly more energetic and mischievous than wild-type ones.

Here are some key behavioral traits of blue axolotls:

• Laid-back temperament
• Bottom dwellers that like to walk rather than swim
• Can be playful and interact with tank decorations
• Use their ruffle-like gills to sense movement and food
• Not prone to nipping like other aquarium fish
• Primarily solitary creatures but can be housed together

Blue axolotls behave much like their wild-type cousins. What sets them apart is their sometimes boisterous personality – they are less shy and sedentary than wild-type axolotls. Their stunning colors make their activities even more fun to watch!

Health Considerations

The genetic mutation that causes the blue coloration makes blue axolotls prone to health problems. Like many piebald or albino animals, they are more sensitive and require special care.

Some key health issues to watch for include:

• Greater susceptibility to fungal infections
• More sensitive skin prone to injury and sunburn
• Eyesight problems due to lack of pigment
• Higher rates of deformities and slower regeneration

To keep blue axolotls healthy, key care tips include:

• Keep tank clean to prevent fungal or bacterial disease
• Use fine gravel or bare bottom tanks to avoid skin injury
• Provide plenty of hides and shade
• Feed nutrient rich foods and vary diet
• Carefully monitor water parameters

With attentive care, blue axolotls can thrive and live a full lifespan of 10-15 years. Their beauty makes the extra care worthwhile!

Caring for Blue Axolotls

Tank Setup

Blue axolotls need a spacious aquarium to thrive. A minimum tank size of 20 gallons for one axolotl is recommended, with an additional 10 gallons per extra axolotl. Axolotls produce a lot of waste, so powerful filtration is a must. Canister filters work well to keep ammonia and nitrite levels low.

Fine gravel or bare-bottom tanks are best as axolotls can accidentally swallow substrate and become impacted. Provide plenty of hiding spots with logs, rocks and live or artificial plants. Axolotls like darker environments, so keep light levels low.

Water Parameters

Axolotls require cool water between 60-68°F. Temperatures above 74°F can be dangerous. Using a chiller is the best way to maintain a stable temperature. The pH should be between 6.5-8. Ammonia, nitrite and nitrate levels must be kept low, with partial water changes around 25% weekly.

A fully cycled tank is essential. Salt baths can sometimes be used as a treatment for disease. Make sure to use aquarium salt, not table salt.

Feeding

Axolotls are carnivorous and will eat live foods like worms, brine shrimp and small feeder fish. Frozen bloodworms, daphnia and brine shrimp are excellent options too. Use feeding tongs to prevent nipped fingers. Feed juveniles 2-3 times a day and adults once a day.

Remove any uneaten food to prevent waste buildup. A varied diet ensures proper nutrition. Axolotls may accidently swallow gravel while feeding, so stay vigilant.

Tank Mates

Axolotls should be kept alone or with other axolotls of similar size. They may attack tank mates due to their predatory instincts. Small shrimp and feeder fish can be added to help keep the tank clean and provide enrichment. Monitor any tank mates closely and remove if aggression occurs.

Avoid housing axolotls with fish that nip fins like barbs, gouramis and bettas.

Why Blue Axolotls Are So Rare

Axolotls come in a variety of colors, but blue axolotls stand out as one of the rarest variants. So what makes blue axolotls so uncommon compared to other color morphs? There are a few key reasons stemming from their genetics and breeding challenges.

Recessive Genetics

The blue coloration in axolotls is controlled by a recessive gene. This means both parents must carry the gene for there to be a chance of having blue offspring. If only one axolotl carries the recessive blue gene, the babies will not express the blue color.

The recessive nature of the blue gene makes it statistically less likely for two carriers to mate. Most axolotl breeding involves a larger gene pool, where blue carriers are uncommon. By chance, it is difficult to get two blue carriers together.

This genetic lottery contributes to the rarity of blue axolotls.

Difficulty Breeding

Even when two blue axolotl carriers are paired, there can be difficulty getting them to breed successfully. Some blue axolotls, especially males, tend to be poorer breeders compared to other colors.

Researchers believe issues with fertility and weaker sperm may be linked to the genetic mutations behind the blue coloration. Limited gene diversity from intense inbreeding also reduces viability. All these factors lower odds of producing blue offspring.

Small Gene Pool

The global stock of blue axolotls started from just a few founder specimens. Blue axolotls descended from very limited genetic lines, bottlenecking genetic diversity even further.

Most blue axolotls today can be traced back to one of the first documented breeding lines developed in the 1960s. From this already narrow gene pool, continuous inbreeding without outcrossing has concentrated problematic mutations.

The tiny gene pool makes it difficult to improve poor fertility while preserving the blue color. With few new bloodlines available, genetic issues accumulate over generations.

Conclusion

The striking blue color of these unique axolotls is a truly marvelous quirk of genetics. While blue specimens are still extremely rare, their one-of-a-kind appearances continue to capture the fascination of aquarists and biologists alike.

With proper care and tank setup, blue axolotls can thrive and display their gorgeous natural colors. If you’re looking to add a rare blue axie to your collection, be sure to purchase captive bred specimens from reputable breeders.

With their delicate health and challenging breeding, blue axolotls should be left to the experts.