Size
Platies are typically smaller than mollies, with adults reaching a maximum size of about 2.5 inches. Mollies, on the other hand, can grow to be much larger, with some species reaching a maximum size of 6 inches or more.
Shape
Platies have a more rounded body shape, while mollies have a more elongated body shape. Mollies also have a longer, more pointed snout than platies.
Fins
Platies have shorter, rounded fins, while mollies have longer, flowing fins. Mollies also have a larger dorsal fin than platies.
Coloration
Platies and mollies both come in a variety of colors and patterns. However, platies are typically more brightly colored than mollies. Mollies often have a metallic sheen to their scales, while platies have a more matte finish.
Temperament
Platies are generally peaceful fish that get along well with other species. Mollies can be more aggressive, especially towards other fish of the same species. Mollies are also more likely to nip at the fins of other fish.
Lifespan
Platies typically have a lifespan of 3-5 years. Mollies have a slightly shorter lifespan of 2-3 years.
Overall, platies and mollies are both great choices for aquariums. They are both easy to care for and come in a variety of colors and patterns. However, there are some key differences between the two species that you should consider before making a decision about which one to get.