Two things to note here. First is the incompatible stocking in this sized tank (260 liters or 70 gallons). This has several aspects. Temperature is one, you have fish needing very warm water, and fish needing much cooler water. There is no middle ground when it comes to temperature which drives a fish's metabolism and affects the internal physiology. I don't know the actual species of a "red tetra," but it may not be at all suited to discus or other cichlids, depending. Combining different cichlids is not advisable with a few exceptions, tank size enters this as well as the species behaviours.
As for the filter, filtration depends upon the needs of the fish with regard to water flow, first and foremost. The "filtration" aspect may be more or less relevant, depending upon the presence (or not) of live plants--and I would note that all the fish mentioned need a good cover of floating plants for shade, and these are incredible for water quality. A reliable canister will likely be your best option. I have had experience with Eheim Pro 2 canisters and Rena (think this is a different name now).