You certainly cannot compare a PBS KIDS show to a Pixar movie creation but it's hard not to compare to what you already know with Nemo or Dory.
The voices of the characters are probably the hardest thing to get around. Many children shows have went to casting children as the voices for characters. In Splash and Bubbles, these are clearly older voice actors trying to change their voices to fit these fish/animals and sounds forced and unnatural.
The best adjective to describe it is "whiney" or sounding like "baby talk."
These voices also make the singing and music difficult to bare. It's neither catchy or pleasant as you may find elsewhere like on Bubble Gubbles.
This is a new show and I don't see it sticking around for long, and if it does - It's clearly do to a contract in place.
Times have changed with animation. Recast the voices and we might give it another try.