Wash and soak the channa dal for 2-3 hours. Wash the fish then add salt and turmeric powder ito it. Chop the tomato & potato into small pieces. Heat 2 tsp oil in a pan. Add the fish and fry till it turns reddish. Crush it in the pan itself and keep aside. Cook the soaked channa dal with a little water, salt and turmeric in a pressure cooker for 1 whistle. Keep aside. Heat 5 tsp oil in a pan.Add the potato pieces, fry for 3-4 mins and remove from wok. Add the red chillis, bay leaf, cumin seeds. Allow to splutter. Add onion to it.Fry till it turns golden brown. Then add Ginger garlic paste along with a little salt . Then add turmeric powder ,Jeera powder,Coriander powder to it and fry it . Cook the masala for 5 mins. Add the chopped tomato and cook for 5 mins for it to soften. Add the crushed fish and boiled channa dal. Mix well and cook for 5 mins. Add 1 1/2 cup of water and bring to a boil. Simmer for 10 - 15 mins. Then add some garam masala powder to it. Then remove it from flame.