"She was the single most quick-witted person I've ever met, with a steel-trap memory that could recall the most forgettable conversations from a decade ago.
"She was the most talented person I've ever known and I'm furious we won't get to see more."
"How can you convey all your love and respect for someone in one post?" he wrote in the caption.
"How can you summarise a decade of friendship and laughter with words alone?
"If you were friends with Naya Rivera, you simply can't. Her brilliance and humour were unmatched. Her beauty and talent were otherworldly."
Darren Criss, who played Blaine Anderson, remembered the star's generosity.
"I was constantly moved by the degree to which she took care of her family, and how she looked out for her friends," he wrote.
"She showed up for me on numerous occasions where she didn't have to, and I was always so grateful for her friendship then, as I certainly am now."
Fan tributes
Rivera was first reported missing last week, after she rented a pontoon boat with her four-year-old son.
He was found alone and asleep in the boat and later told police his mother had never returned after swimming in the lake.
Speaking at a news conference on Monday, Ventura County Sheriff William Ayub said a body had been found near the surface of the water in the north eastern section of the lake.
Police were "confident" they had found Rivera, based on location, clothing and physical characteristics. An autopsy and dental records will be used to confirm her identity. There were no signs of foul play.
Media playback is unsupported on your device
Media captionVentura County police said there was no indication of foul play
The discovery came exactly seven years after Rivera's Glee co-star, Cory Monteith, was found dead in a Vancouver hotel room of an overdose of heroin and alcohol.
Lea Michele, who was the show's lead actress, posted black-and-white photos of both actors on her Instagram story in tribute.
Many cast members also re-posted a video of Rivera and Monteith signing autographs for fans outside Paramount studios in Hollywood.
The original poster had highlighted how "Naya and Cory always took the time to meet fans and talk with them".
"They were so kind-hearted and they loved and appreciated us so much," she added.
Fans also posted videos of Rivera's most memorable performances on the show - especially the song If I Die Young, which she sang in an episode commemorating Monteith's death.
Others shared how important it had been to see Rivera portray a character who was both Latin and LGBT.
"Naya was a powerhouse not just on Glee, but in life," wrote Twitter user @IssyFields.
"Her portrayal of Santana gave me the confidence to be unapologetically myself and made millions of voices heard. Glee has memorialised her beautiful talents forever because she is, and always will be, a hero."
Image copyrightGetty ImagesImage captionRivera attended the 2012 Golden Globes with her co-stars (L-R) Jenna Ushkowitz, Kevin McHale, Lea Michele and Amber Riley
Singer Bryana Salaz said she "didn't realize the impact" Rivera had on her life growing up as "the first POC, LGBTQ character I saw on screen.
"I grew up listening to you sing, being inspired by the girl on Glee who looks like me and is unapologetically herself. You changed so many lives. Rest easy angel," she added.
"Glee gave me the strength I needed to come to terms with my sexuality," added YouTuber Luke Birch.
"Seeing characters like Santana gave me so much hope and courage. You helped an entire generation of LGBTQ+ people, Naya. A talent like no other. Rest In Peace."
This website uses cookies so that we can provide you with the best user experience possible. Cookie information is stored in your browser and performs functions such as recognising you when you return to our website and helping our team to understand which sections of the website you find most interesting and useful.
Strictly Necessary Cookies
Strictly Necessary Cookie should be enabled at all times so that we can save your preferences for cookie settings.
If you disable this cookie, we will not be able to save your preferences. This means that every time you visit this website you will need to enable or disable cookies again.