While you might think the only reason to decorate your fish tank is for appearance, that’s actually of secondary importance when it comes to your pets’ well-being. Fish need tank décor because the various structures and plants provide hiding places that give fish a feeling of security. In their natural environments, which for most common aquarium fish are ponds, rivers, and streams, fish dart into plants, under rocks, or behind sunken logs to avoid predators. And while there might not be any predators lurking in your fish tank, your finned pets still can become stressed and even ill if they feel too exposed. However, it’s perfectly fine to limit your tank décor to just a few plants, a rock or two, substrate, and a background.