Rinse the fish and mix a little bit of salt and turmeric powder on it. Set aside.
Peel the shalgam/turnips and slice into small pieces.
Heat a kadahi/ korai with oil and then add onions to it. Fry the onions until they become soft. Add the turmeric and coriander powders, garlic paste and beetroot slices. Stir and the fish slices. Add water as needed for preferred gravy. Allow to cook.
Once the beetroot and the fishes are well cooked (they will become soft), spinkle the green chillies. Simmer for 2 more minutes, and then take the pan off the heat.