I have heard that if you can fish the bones are soft. Well I bought a carp at the Asian market to give it a shot. Fish tasted great but bones were still hard. Suggestions? What did I do wrong?

i dunno, but, i ate some pickled walleye in N Dakota once and it was delicious. no bones though.

Did you put in a little vinegar?

Need to pressure cook first.

I also cooked and ate a carp about 2.5-3# a few years ago. It was amazing how yellow and oily the meat was when I was preparing to cook it. I only scaled, removed the head, and intestines. I then cut the fish in about 2.5 inch sections. Placed in my pressure cooker with about 1.5 Tablespoons of Old Bay. Cooked it at 15# of pressure for 30 minutes. It was a great tasting beautiful white meat. If I was doing it again I'd go for 45 minutes to maybe an hour in order to more soften the bones. The bones remained hard but the meat was easily remove and I do believe if cooked longer they would be like the bones in processed Tuna or Salmon and just a chalky edible piece.
Carp have a bad rap as a food fish but I do believe this is false information passed on by folks who just don't like the fish period. They are easily caught and cooked and just as good as most other fish when cared for, process right and pressured or steamed cooked.
I do catch and eat blue cat weekly so I'm very partial to it, but if the situation presents itself anytime in the near future I will once again have a meal of small young carp. Don't knock it until you have tried it.

This

Score it in a diamond pattern through the meat and stop just shy of th skin and fry in really hot oil. That's the way they do carp and suckers in the midwest. Scoring cuts the softer bones into small pieces and the hot oil makes them break down.

https://www.motherearthnews.com/real-food/canning/canning-fish-quart-jars-ze0z1407zsie

Bones said to soften under the pressure canner process. Never have I done this, but there�s a lot on the web about it.