What can I add to this food to make it taste good?
This question may get closed, but there are still some standard answers why broth doesn't taste good.

Number 1) salt, broth must have salt or some seasoning that gives the broth some character, otherwise no matter how else it may be good, it will taste dead and flat.

Number 2) there are certain triads of veg that need to form the basis of broths even if you use other ingredients in addition (like fish or chicken). Mirepoix is one of those, which is onion, carrot and celery. Another is the Cajun holy trinity of onion, peppers and celery, or the French duxelles of onions shallots and mushrooms. There is also the Portuguese refogado of onions, garlic and tomato.

Just a few days ago I made a ramen noodle soup that was cabbage based, but I still started with a mirepoix first, added cabbage and fish sauce, then after making the broth threw out all the spent veg, and tossed in fresh cabbage and mushrooms a few minutes before serving.

Make one of these the basis of your broth, and remember to salt "just enough" salt, not too
Much or too little. It requires tasting to get it right.