Removing stucco should be doable but concrete doesn't really stick to itself so that part might be difficult. If you put the concrete on couple inches thick like building a bowl in a bowl with the base acting like a form that might work.

There are bonding materials but make sure you find out how thick the top layer needs to be or you could find yourself in the same situation you are now. I wonder if trying to remove the blue paint might be easier?

The blue is kinda already coming off

and i got a concrete additive to help bond i hope that works

I'm sure this was a fun project at one time but I think a makeover is overdue.

Have you thought about something more appropriate for the desert? I would remove everything, even out the soil, and lay down some crushed granite or gravel.

Reserve a few stepping stones for a little path and natural boulders to place here and there. Plant some aloe, a yucca and some flowering succulents, that sort of thing.

I'd be nervous about whatever you use to refinish the pond killing off the fish.

I like tracefloyd's idea about doing something else with it.

I agree with tracyfloyd. take out the pond. This will be impossible to clean. the while thing will become covered in bacteria and algae and your fish will die. plus it will look terrible. neither you nor your guests will ever be comfortable because their only thoughts will be about how those poor fish are slowly dying- both in their own filth and from the leaching of concrete and DIY chemicals.