Not just crude but inaccurate and full of plot holes
Not only is it crude, it's educationally useless. The setting is a dystopian world but underwater. They tell each other to shut up frequently, use violence as a first response, and nearly every character is egotistical.
Then the inaccuracies... a dumbo octopus' grandfather is a kraken. Sea life survives lava. Subway cars run underwater. A moray eel accidentally eats a bunch of sea creatures and then barfs them back up, perfectly intact. I could go on and on.
I put 9 and up but really am not sure why anyone would watch this with a plethora of good movies out there.