Aquatic Blue Rangers And Mermaids: Dyna Blue And Blue Lightspeed Ranger!
Well Power Rangers does get ideas from very old Super Sentai seasons then modifies them. Chad Lee himself feels like a huge tribute to Hirohisa Soda's aquatic blues like Yousuke Shima, Ryuta Nanbara and Ken Hoshikawa instead of his GogoFive counterpart Nagare Tatsumi. If we're going to go before Soda, Kinya Samejima had a shark motif going on. Chad being different than Nagare ended up introducing something new for Power Rangers.
I guess Power Rangers does have its own fair share of ideas from the Takeyuki Suzuki era.