If you have trouble eating plain brown rice, make up some Gomashio and sprinkle it liberally on the rice. Gomashio is yang also. make sure you roast both the seeds and the salt before crushing them together, as that will yangize them further and release the oil from the sesame to coat the salt.
use this condiment on other foods as well, it is tasty.
Fish every day may be excessive eventually, and you would need to swing yourself back into balance by cutting back and increasing grains and veggies.
I believe you are on the right track by yangizing, but be conscious that the way to health is through balance and harmony. If you have been eating meat and dairy, especially meat, you should eat lots of veggies, especially sea and green leafy and roots to put minerals back in your body that meat depletes.
experiment with alternative ways of incorporating unprocessed whole grains into your diet, such as veggie/grain/bean pies with a flavorful sauce or casseroles. be careful not to use too much oil because it is very yin.
Good luck, keep trying.