lettus slug ?

[Thomas Berk]

purchased one of these a few weeks ago cause he was to interesting to pass up, I know bad reason, I was told he ate hair alge off live rock true or false, if false what do they eat?

 

[greenbean36191]

Well it depends on which species you got. There are at least 3 species offered in the hobby. At least one of them feeds on hair algae. One specializes in Caulerpa and probably won't touch hair algae. The other's diet isn't well known, but it probably feeds on calcareous macroalgae or hair algae.