To see a manatee in your dream, represents your passiveness in a situation. You are lacking ambition and drive. Alternatively, it represents someone in your life who is lazy, slow or gentle.
Gentle, docile, unassuming, innocent, harmless, content. Susceptible to the environment (as the manatee is an endangered species). Dreaming of this animal can represent:
Having too much of one of these qualities, or that you could benefit by being less this way
Not having enough of one of these qualities, or that you could benefit by being more like this
Someone or something in your real life with whom you associate one of these qualities (an event, situation, threat, etc.)
For more clues, pay attention to what the animal was doing or any particular characteristic that stood out.