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Difference Between Platys & Swordtails

Both swordtail and platys fish belong to the Xiphophorus genus and basically prefer and require the same sort of conditions for aquarium life. They can generally live peaceably together and with other live-bearing fish such as mollies and certain species of tetra. Nevertheless, differences, though often slight, do exist in the morphology, environmental preferences and other characteristics of these fish.

Body Shape
- Male swordtails are well known for the lower rays of their caudal (tail) fin that extends into a sword that often duplicates the length of the fish's body. The male platy doesn't have a sword. In the wild, the swordtail has an olive green back, greenish yellow sides, a yellow belly and a red zigzag line down the side. Domesticated swordtails can incorporate many colors, including bright orange, orange with black fins or markings, golden or black. Interestingly, the colors of a platy female resemble the colors of a wild swordtail male, down to the zigzag red line. The platy male is brownish yellow.
Size
- The swordtail male, measures 3 1/4 inches long excluding the sword,and the female can measure up to 4 3/4 inches long. The platy is fatter than the swordtail but shorter, the male measuring 2 1/4 long and the female 2 3/4 inches long.
Food
- Both fish take both live and dried food. The platy likes some fresh vegetables, such as spinach or algae, now and then. Swordtail adults will cannibalize their young if they have a chance; before the birth, put the adults in a breeding trap for the young to escape. You can feed the fry powdered food almost immediately. Platys don't eat their young, and breeding is not problematic for them.
Water and Light
- Platys can take a wider range of water temperature --- 68 to 77 degrees Fahrenheit, as opposed to the swordtail's preference for 72 to 73 degrees. The platy likes the water just slightly more alkaline: an 8 pH as opposed to the swordtail's 7-8 pH. Change the platy's water --- at least partially --- on a fairly regular basis. Platys like medium-hard water, or water with a mid-level mineral content, and the swordtail prefers medium to extremely hard water. Platys prefer a small amount of floating plants in their tank such as floating fern or water velvet, while swordtails like to swim more freely. Both fish prefer the level of typical summer light; the platy likes lots of light (about the level of a 6500-Kelvin bulb), while the swordtail likes a little less light (about 6000-Kelvin). Lighting considerations also depend on tank size.

Animals & Science