Ilish Fish Recipe Guide

: How To Clean And Prepare Hilsa For Monsoon Cooking

Quick Summary

Hilsa fish is the darling of Eastern India, particularly among the Bengali community, where it is called ‘ilish maach’ and fetches an exorbitant price depending on its seasonal availability. The bones of this fish make it tricky to eat as well as prepare, because they are slender and almost as thin as hair, and its oily flesh is also prone to tearing if handled roughly. So head to a Kolkata fish market and learn how to spot a fresh hilsa, descale and clean it, cut it into the right pieces, prepare different hilsa recipes, and store what you don't use right away. 

Deep Dive

Hilsa fish, or ilish maach, is an anadromous fish, meaning it splits its life between saltwater and freshwater. The fish is born in rivers, spends its adult life in the sea, and then migrates back upstream to spawn, a journey that researchers studying its population and genetics have traced across estuaries and multiple river systems in the Bay of Bengal. That migration is also why a good hilsa fish often arrives with a bellyful of roe (fish eggs), considered a delicacy that gets prepared into a handful of dishes. This fish is a good source of omega-3 fatty acids, which the body can’t produce on its own. These polyunsaturated fatty acids support brain and heart health and lower blood pressure. So here’s how to clean, spot, and cook this delicious fish.

How to Check a Hilsa Fish for Freshness Before You Buy

Since hilsa is expensive. A quick check at the market saves you the trouble of dealing with spoilt fish later. There are ways to spot the freshness in whole fish, as outlined by the FDA's guidelines on selecting seafood, which also holds for hilsa as much as any other fish:

• The eyes should be clear and slightly bulging, not sunken or cloudy.

• Gills should be a vivid red or pink, not brown, grey or slimy.

• Scales should look glossy and metallic and be taut and close to the skin, rather than flaking off.

• The flesh should feel firm and spring back when pressed, not stay dented.

• The smell should be mild and briny, reminiscent of the sea, and not pungent or ammonia-like.

As a conscientious fish eater, it is also important to consider sustainable eating practices, as this fish is prone to overfishing. So, buy just what you would consume, mindfully, and not in bulk, so no extra fish goes to waste or rots in the fridge; around 150 to 200 grams per person is a decent amount. Have this fish when it is in season and avoid it during the off-season, especially during the October-to-March breeding stretch, so the fish can spawn and sustain their numbers in the wild.

How to Descale and Clean Hilsa at Home

Usually, the fishmongers will descale, clean and cut the fish for you; in such cases, know your cuts and relay them to the seller. But in case you get your hands on hilsa outside such fish markets, you will have to do these on your own. It’s quite straightforward and needs to be done in order:

1. Have a firm grip, like you would a child, on the tail of the hilsa fish and scrape a blunt knife or a descaler from tail to head to get rid of the scales. Make sure you do it over a sink or a sheet so it's easier to discard the scales later.

2. Rinse the fish under running water to remove any loose scales, as soaking can wash away its natural oils.

3. Trim all the fins with a sharp knife or kitchen scissors, keeping the cuts shallow, so you don't nick the flesh.

4. Slit the belly from the vent up toward the head and remove the innards. Harvest the roe for other dishes, if present.

5. Pat the fish dry with a clean cloth before cutting.

Tip: Fish odour can linger, so make sure you secure the area you are working in and work quickly. Dispose of the waste immediately and clean up properly afterwards. Use gloves if the lingering odour bothers you.

How to Cut Hilsa for Different Hilsa Recipes

Bengali kitchens have their own vocabulary for hilsa cuts, and the one you reach for depends entirely on the dish. This fish is an important part of the ‘maach bhaat’ traditions that are followed in the region. A medium-sized hilsa fish is typically divided into the muro (head), lyaja (tail), and the body, cut widthwise for curries and pan-frying. The front, softer portion is called the peti and the tail-side, bonier portion is called the gada. 

For a fish curry or jhol, the fish is cut crosswise into 1- to 2-inch pieces that hold their shape even when added to gravies. For dishes like ilish paturi or bhapa ilish, where the fish is wrapped in a banana leaf or steamed in a sealed dish (like a steel container), slightly thicker pieces work better for moister, juicier results. For a simple fish fry, thinner pieces are great because they crisp up faster and use less oil. The head and tail of the hilsa fish aren't wasted either: they're commonly fried and added to curries for flavourful dishes.

How to Debone Hilsa Fish

Deboning isn't traditional, and most curry recipes are cooked bone-in, since the bones soften with longer cooking and Bengali households learn early to work around them. But if you're making something like a fish cutlet or a dish for someone unused to picking bones, it can be done:

1. Lay the cleaned fish flat, belly facing you, and slide a sharp knife along the backbone from head to tail, lifting the flesh gently as you cut to release one fillet.

2. Repeat on the other side to free the second fillet.

3. With each fillet skin-side down, locate the row of fine rib bones and slide the knife just beneath them to lift them away without tearing the flesh.

4. Run a finger along the fillet to feel for any remaining pin bones and pull them out with tweezers.

This is fiddly work given how fine and numerous hilsa's bones are, so it's worth doing only when the recipe specifically calls for boneless pieces.

Matching Hilsa Fish Cut to the Dish

How to Store Leftover Hilsa the Right Way

Raw fish, including hilsa, is highly perishable, and FDA and USDA food safety guidelines state that it should be refrigerated or frozen within 2 hours of purchase, or within 1 hour if the temperature is above 32°C. If you plan to cook it within a day or two, store it at 4°C or below, ideally on a tray of crushed ice without letting the flesh sit directly in melting water. 

For longer storage, wrap the fish tightly in plastic wrap, foil or moisture-proof paper and freeze it at -18°C or below, where it stays safe indefinitely, though quality is best within a few months. Thaw frozen hilsa fish gradually in the refrigerator overnight, or, if you're short on time, in a sealed bag submerged in cold water, changing the water every 30 minutes. Never thaw it on the counter at room temperature. Once cooked, leftover hilsa can be kept in the refrigerator for 3 to 4 days.

Getting This Right Makes Hilsa Recipes a Breeze

None of this preparation is complicated once you've done it a couple of times, as hilsa is delicate. If cleaned and cut well, and the recipes are followed well, the fish pieces will hold their shape even after they hit the curry and are placed on the serving plate. For most dishes, the deboning during eating is part of the hilsa relishing experience, so mentally dedicate that hawk-eyed gaze towards the fish’s elusive bones that often prick many a hilsa muncher’s throat.