Photo of the Day: There are over 3,000 species of colorful sea slugs that populate our oceans. Their bright markings are meant to indicate their toxicity. . . . #POTD #photooftheday #picoftheday #seaslug #colorful #ocean #oceanlife #marinebiology #aquatic #underwater #underwaterphotography #nature #naturephotography #closeup #macro #neon #strange