They do very well as just one specimen. For those who add extra fish, know the flowerhorn’s tendency for territorial aggression and be ready to rearrange your tank. The Marbled Hatchetfish you currently come across in the trade are wild-caught, so we advocate quarantining them in advance of incorporating them https://aquariumfishonline.food.blog/2024/02/19/4-things-new-aquarists-keeping-flowerhorn-fish-should-maintain/