Description: keeping swordtail fish in the aquarium requires special water and tank treatments. Here is the basic guide. Keeping swordtail fish is a popular hobby, especially since swordtails require less difficult efforts to keep than more exotic fish. However, taking care of swordtail fish in the aquarium still requires proper maintenance, especially if you want to breed them for business. Here is what you need to know about keeping swordtails. Ideal Water to Keep Swordtail Fish Swordtail fish are natives to rivers in North and Central America, and they prefer warm or tropical water. However, they can adjust well to water with 65 to 82 degrees Fahrenheit (around 18 to 28 degrees Celsius). Their natural habitats have enough underwater plants to nibble on and hide, especially for the newly-born fry. The best water pH for the optimum living condition is between 7.0 and 8.4, with moderate alkaline level. Swordtails also live better in hard water with 12 to 30 dGH. While the fish can...