Insects
Adult two-lined salamanders subsist primarily on insects including spiders, centipedes, earthworms and snails. Their larvae live in water and eat small aquatic insects including mosquitoes and stoneflies.
Crustaceans
Two-lined salamander larvae frequently eat small, aquatic crustaceans including crayfish. Copepods, small planktonic crustaceans, comprise a substantial portion of their diet.
Other Salamanders
Two-lined salamanders are opportunistic feeders and will eat most protein material they can catch. In some cases, they eat smaller salamanders or salamander larvae.
Plant Matter
Two-lined salamanders are carnivores, but they still require plant matter to remain healthy. In the wild, they acquire small quantities of vegetables by consuming insects and other animals that are herbivores or omnivores. In captivity, all food items should be "gut loaded" by feeding the prey 24 hours before feeding salamanders.
Water and Calcium
Water and calcium are two vital components of a two-lined salamander's diet. In the wild, salamanders metabolize calcium by absorbing vitamin D from sunlight. In captivity, however, they must be given a calcium supplement dusted on their food and be exposed to artificial UV bulbs or direct sunlight. Because two-lined salamanders are amphibians, they absorb water through their skin, which must remain moist. Without constant access to water, salamanders quickly die.