When I inherited my baby axol, freeze-dried Tubifex cubes were its staple diet, but I found this at
http://www.axolotl.org/feeding.htm :
"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."
and this at
http://www.axolotl.org/health.htm :
"Some physical problems are related to nutrition. Caudates (a term used to describe newts and salamanders) tend to have difficulty dealing with large quantities of fats and oils in their diet. White worms and tubifex are the most commonly quoted high fat foods. Dog food can also contain a high proportion of oils and fats. When fed exclusively on these foods, occurrences of sclerosis of the liver increase.... Again, these shouldn't be fed as the sole food but rather as an occasional treat to avoid health problems."
Needless to say, and since my axol was sick for a while, I chose not to take any chances and stopped feeding TubiFex altogether. Now I rotate between bloodworms, brine shrimp and reptomin floating food sticks. Since I still have them, for a very rare treat, I may throw in a small nibble of TubiFex, but not more than about once a week or longer.