Carvinore or Herbivore?Edit
Axolotls are carnivores, implying they require a meat-based diet. They have rather rudimentary teeth, designed for gripping rather than biting or tearing. As a result, their food is generally swallowed whole, so anything they want to eat must fit into their mouths.
When They Bite, What Happens?Edit
When a hand-fed axolotl becomes accustomed to people, it may occasionally latch onto a finger. You can feel these little teeth quite distinctly. This is a curious experience, rather than a painful one, because the axolotl hasn't the strength to pierce human skin, so don't be afraid to try it.
The Axolotl's teeth come into their own when trying to grip something slippery like an earthworm. The worm will wriggle but it will find it very difficult to escape the Axolotl's mouth. If the worm is too large to swallow completely, the Axolotl will eventually give up and let go. Large food is a problem when you don't have biting teeth! The name "Ambystoma" means cup-mouth, and axolotls do have large, wide mouths. When an axolotl wants to eat something, it opens its mouth suddenly and water rushes in, along with the food or anything else around (such as parts of other axolotls, or pieces of gravel). This vacuum action often results in a sudden lurch of the axolotl up into the water and then the animal settles down again.
Dead or AliveEdit
Axolotls will eat live or dead food. The movement of live food like a worm is a great stimulus for the axolotl to "snap", and indeed, for newly hatched axolotls movement is the only stimulus to which they will respond.
Earthworms are a good food source for adult axolotls, but be sure to get them from a source that doesn't use chemicals (such as an organic garden). Better still, raise them yourself if you have the space. Water-based live foods can be risky because they can be a source of disease. However, if taken from fish-free waters, they tend to be a lot safer (no hosts for the parasites usually means no parasites). Tubifex, although a good food, is not nutritionally balanced for axolotls, and Tubifex can also carry parasites, dangerous bacteria, and other diseases. There are also reports that Tubifex attack salamander eggs. Tubifex are often mistakenly called bloodworms in the US, and shouldn't be confused with the true bloodworms, the larvae of chironomid midges. Freeze-dried and frozen Tubifex are safer than live, although freeze-dried isn't very nutritious.
Ghost Midge LarvaEdit
Bloodworms are midge larvae, and not worms. They get their name from their bright red colouration. They live in the sediments of ponds, where they feed on detritus. They are a very nutritious and well balanced food, but get them from fish-free waters. I find frozen bloodworm cubes indispensable when raising young axolotls, and I heartily recommend them. Blackworms, genus Lumbriculus, are an aquatic relative of earthworms. They are much thinner and smaller than earthworms, and they are a dark brown colour. They have a similarly high nutritional value to that of earthworms, making them a very good choice from that point of view. They can be cultured in captivity, but, at least in the USA, they are commonly and conveniently available in aquarium shops. Wild caught, they can pose the same disease problems as Tubifex, so again, get them from fish-free waters.==Whiteworms== Whiteworms, and the closely related Grindal worms, are commonly used to feed juvenile animals. They're a good food source, but they tend to be rather fatty and oily, perhaps because people often feed them with milk-soaked bread. Bloodworms and blackworms can be fed as a staple, provided that there is a little variety occasionally to offset any imbalance, while whiteworms and grindal worms should be used as a treat or a temporary rearing food.
Foods like Daphnia are a good staple, being as nutritionally balanced as brineshrimp. Wild-caught, these still pose a risk of disease. Home-cultured Daphnia, on the other hand, are a great source of food for larval axolotls. Daphnia also make a good treat for axolotls up to 18 cm long (7 inches). Larger axolotls tend not to notice Daphnia. They are also an inexpensive food if home-cultured.
The Indiana University Axolotl Colony, when it still existed, fed its axolotls with high protein and vitamin fortified pellets designed for salmon (5 mm diameter for adults, 3 mm for younger axolotls). The pellets are 45% protein and 20% fat.