Of all the cool things about her Nashville home – from the cozy nursery and pool to the music “jam room” – Hayden Panettiere may be most enamored with…the fish tanks. “It’s my passion! You will never see anybody geek out as much as me about fish,” the Nashville star tells PEOPLE.

“The fish tanks are my happy place.” In fact, hanging above one of two enormous aquariums in her 4,500 square-foot house is a framed sign that reads: “This is My Happy Place”. For Panettiere, 27, who shares the home with partner Wladimir Klitschko and their two-year-old daughter, Kaya, her beloved fish, coral and even sea anemone have long been a source of comfort. “I could literally sit on a stool in front of my fish tank and just stare at it and watch,” she says.

“It makes me feel peace. It makes me feel calm, and I can feel my blood pressure going down. I know some people might think it’s crazy but they actually interact with you. It’s kind of like being a mom – in a different way!”

Another budding fish-fan? Her daughter, Kaya. “All she wants to see when I FaceTime her is fish – she says, ‘Show me the fish!’,” says Panettiere, smiling.“She loves Nemo, Dory, and all the fish!”While the actress regularly rescues animals and fosters dogs before placing them in homes, she feels an actress’s life doesn’t lend itself to raising pets. “Sitting in a trailer is not the life they deserve,” she says. “So, fish are perfect for me!”

For much more on Panettiere’s Nashville haven and an inside look at celebrity homes, please pick up this week’s issue of PEOPLE, on stands Friday.