Lately I have found that eating fish with vegetables is more balancing for me than taking my chances with a token vegetarian dish. Just be wary of too many fish based meals in a short space of time if you are sensitive to strong foods or have a tendency to become too yang and contracted. Some people find fish balancing while travelling, others find it unbalancing. The trick it to listen to your body and see how it responds. Some people balance fish with fruit and others with more vegetables or raw vegetables.
Some people just find that it naturally balances out.
In the absence of other grain products I ate a plain baked potato with the fish and steamed vegetables and felt surprisingly balanced afterwards. Most restaurants will have a fish of the day or fish dish on the menu. If you eat fruit, take a few organic apples to munch on, or other fruit in season that travels well. Snap dried or ordinary dried fruit in small amounts can also be useful. Be wary of the multitude of supposedly healthy snack foods available.