10-20% of a turtles diet is plants. Most species are considered carnivores.
A turtle's diet varies greatly depending on the environment in which it lives. Adult turtles typically eat
aquatic plants, invertebrates such as
insects,
snails, and
worms, and have been reported to occasionally eat dead
marine animals. Several small freshwater species are carnivorous, eating small fish and a wide range of aquatic life. However, protein is essential to turtle growth and juvenile turtles are purely carnivorous.
Sea turtles typically feed on
jellyfish,
sponges, and other soft-bodied organisms. Some species with stronger jaws have been observed to eat
shellfish, while others, such as the
green sea turtle, do not eat meat at all and, instead, have a diet largely made up of
algae.
en.wikipedia.org
Again, in the water, a turtle can no longer be consider "slow."