As far as I know, the only place you can see Delphine show in Tokyo is Aqua Park Shinagawa which is at Shinagawa Prince Hotel in central Tokyo. Just take JR (yamanote or keihintohoku) to go to Shinagawa station and make sure you go left at the exist and go down stairs, it’s in front of you.
Accessibility is good and there is also mid sized aquarium and small rides (merry go around and viking ride only..) so kids would really enjoy it.
Last time I went there was more than 10 years ago…at that time the aquarium is not so good but this time it has been upgraded!
But i say the BEST aquarium in TOKYO is not this one, the best is KASAI RINGKAI KOEN’s aquarium. I get to that later!