Yes, Flowerhorns can live with Oscars in the same tank as long as certain precautions are taken. In general, both species have similar needs and require a large aquarium of at least 55 gallons or more. When setting up the tank be sure to provide ample hiding places such as plants, rocks, driftwood and other decorations that will help keep stress levels down for both fishes. The water should also be kept clean by doing weekly water changes of around 25-30% and making sure to maintain good filtration. The most important factor though is providing each fish its own territory; this means avoiding overcrowding the tank or having too many Oscar’s compared to Flowerhorns which may lead to fights over territory or resources. Lastly it’s recommended that you feed them different foods so everyone gets their fair share of food without competition from one another. By following these tips you can ensure successful cohabitation between your Flowerhorn and Oscar!