Xiphophorus helleri The swordtails are very good fish for beginners. They have vibrant colors and are easy to maintain in the tank. The most common color for these fish is the orange/red colors. These fish do much better in groups, in about 4-6. Just like in most animals, these fish get very competitive whenever it is mating season. During this time, the females prefer plenty of hiding space in the tank, even though the tank doesn't need to be that big for the fish to thrive. A good ratio for the Xiphophorus Helleri is 2:1 (females:males). Swordtails will eat anything really, but it is advised that flake food is given on a daily basis. As you can imagine, these fish get their name from the sword at the end of the tail.