What are their enemies?

Dear Debbie,
A gastropods first line of defence is its shell. So youe would think that sea slugs, which have lost their shells, would be 'sitting ducks' for any hungry animal passing by. Sea Slugs, and nudibranchs in particular, have developed a fascinating variety of ways to defend themselves. If you have a look at the Defensive Strategies Page you will see a number of links to pages with more detailed information.

For animals with such complicated defence mechanisms, we know remarkably little about what actually eats them. I have started a Predation Records Page to accumulate this sort of information so have a look there to see how little we know. I hope this will give you and your daughter enough information for yur school project.
best wishes,
Bill Rudman