Difference between Fissidens fox & Fissidens fontanus

As you can see on the pictures Fissidens fox is smaller than fontanus. Both are grown in the same tank (high light, CO2 supply, EI ferts dosing) and they are tied to the inox wire mesh at the same time. Fissidens fontanus growing a little bit faster than Fissidens fox. Both are true aquatic and easy to grow, even in the tanks without CO2 supply and dosing ferts.