I cook this Japanese style vinegar fish stew quite often recently. It is easy to cook, healthy and most important we love it. I got the recipe from NHK cooking program, but I always cooked it with whatever was available in the kitchen.
No exact measurement for this recipe, taste along the way to get the flavour and sourness I want. To make this, bring together water (just enough to cover ish), white vinegar, sugar and light soy sauce in a small pot, then bring to boil. Turn the heat to low, then add in fish, ginger, onion and carrot. Let it simmer over low heat for 10-15 minutes with lid on, add salt to taste. Serve warm or in room temperature.