I was wrong.
I flipped the "Mrs Lee's Cookbook" by Shermay Lee and took reference from there.
The otah does not taste bad but it is not what I want my otah to be like. It is the texture.
It is rather rubbery when it gets cold ...
I bought fresh mackerel to make my own fish paste. I think that is where the problem comes from. I think it is wiser to get the fish paste from fishball seller. They have adjusted the consistency well. I think I should have added more water into the fish mixture to have a smoother texture.
I will not share the recipe now as it needs major revision. I promise I will conquer the otah!