You need quality food, as all fish foods are not equal. You also need food specifically intended for upper fish and food intended for lower fish.
Flake and micro pellet foods will provide food for the upper fish (and the pellet will likely appeal to the hoplo catfish too). Sinking pellets/disks/tabs are intended for substrate feeders.
Quality brands are those with good ingredients such as whole fish rather than "meal," plus they do not have unnecessary (sometimes harmful) additives. Omega One and New Life Spectrum are two brands I use, and there are others that members will undoubtedly mention.
Feed sparingly; upper fish foods should be gone in seconds. Sinking foods are intended to remain so substrate fish can slowly consume them; some of these are still being chomped on an hour or more after I add them, depending upon the fish.
Feed once daily; manufacturers all say several times, but only fry need this much food. And it doesn't hurt to miss one or two days a week; fry need more regular feeding, but not mature fish, and missing a day or two will benefit. Never feed before you intend doing work (such as the weekly water change) on the tank. Feed preferably earlier in the day than later, and always no sooner than 45-60 minutes after or before the tank light comes on/foes off. Nocturnal fish can be fed in darkness, but that is different.
A good quality sinking catfish pellets/ good quality flake food you should feed a variety of foods feed at least once or twice a day. some live food should be added to the diet at least two or three times a week
The mention of live food twigged me to the fact that I forgot about frozen (and live). It is not necessary to feed live food at all, but you can. Frozen foods (fresh frozen, not freeze dried which is very different) make nice treats. Frozen bloodworms should only be fed once a week if at all. Frozen daphnia is good, and frozen brine shrimp.
The quality of prepared (dried) foods is very high, and will provide all nutritional needs for nearly all aquarium fish. They are convenient too.
Feeding live food is a matter of choice I personally believe it is better than any prepared foods especially when it comes to getting fish into breeding conditions also Feeding live foods to your fish provides them with important nutrition and protein that most definitely helps with there growth and colour.
All my fish are fed on a variety of foods mainly live food, frozen food are good but we'll never be as good as live food
Yes, this is a good food, and it feeds both upper and substrate fish (provided some get down to the substrate). Corydoras particularly love them, and on CorydorasWorld this is a recommended major cory food item.