Some freshwater fish do tend to be fatty and some say they taste a little muddy. This is especially true with the larger fish, so if you are catching plenty just keep the smaller ones, “legal size of course” and release the big fella’s because the smaller fish are much tastier. Freshwater fish do tend to be very active during the warmer months of the year when the rivers are flowing and this is when they feed to fatten themselves up for the winter months when the rivers have very little flow and they do not feed as actively. Fish caught in dams and impoundments are almost always very fatty because there is no flow in the water to keep them moving.
We always fillet and skin all our fish because the muddy and weedy flavour comes out of the skin when the fish is cooked if the skin is left on. Place you fillets in your fridge or esky for an hour or two to cool them down, now you will be able to easily see the fat layers on the fillet, take a very sharp knife and carefully slice off the thin fat layer on the outside of the fillet and around the belly of the fillet. This is a great help in removing a lot of the fatty flavour. To remove the muddy taste, just place your fillets in a dish and cover with salty water and add a tablespoon of vinegar and put them in the fridge for at least an hour, it is that simple, it will clean them and they will taste great. Another way is to soak the fillets in milk and maybe add a little crushed garlic if you like. This treatment also works a treat on your not so great tasting saltwater fish.