Sharks still attack and cause damage when in Vanish.

Thanks I'll look into this 

They will only attack you if you attack them first. Many of the rust NPC's have a targeting component that gets triggered when attack. Vanish will stop them from sensing you but it wont stop them from targeting you if you attack them first. Doing this would make the performance of the plugin very inneficient. It is highly recommended to not use weapons while in vanish.