we eat fish too at least once a week - tilapia, trout, flounder. Get my protein also from chicken, low-fat cottage cheese snacks (love them!), and occasionally ground beef, pork and steak. I noticed that I like each meal to have at least a serving of protein/meat, it keeps me fuller longer. I also love Balance Bars, but they don't keep me full for too long - except when I'm active. They are great when you're out and about, and don't have time for lunch, and great alternative to fast food. Personally I've found that recommended amount of protein is not quite enough for me - I prefer to get more, because it keeps me full longer and seems to give more energy and overall well-being. Two cautions on protein: Big fish (like tuna, salmon and shark) tend to have higher levels of mercury, so limit their consumption and instead increase consumption of small fish. There is such a thing as too much protein. If you eat too much for your body to metabolize, your kidneys will work hard to expell it from your body, which can theoretically over-tax them. But if you're eating a 1200 calorie diet, and it is balanced, I don't think you're in danger of that. Just listen to your body closely and monitor how you feel, and you'll be fine.
You're doing great on exercise and food. Just make sure you get at least 1000-1200 calories a day. Lower may put you in "starvation mode".
All the best!