I am keeping this plant outside in a 10g aquarium and it is by far the fastest growing plant I have ever seen. I got it 2 days ago and it was like 3" each and now they are like 9". Amazing that there was a day of it being dormant but it really just takes off.
I looooove this plant. The pictures to the left are of submerged growth. Its a very dainty and feather plant. It grew in my low tech low light tank. But very very very very slowly. Like a centimeter a month. In my low tech high light tank it grows about an inch a week. Which is just fine with me. I'm certain that the addition of CO2 could turn this into a fast growers. And probably gives it a more compact appearance. Over all a very very pleasant plant.
I have a seen this plant locally at a place where they sell it for ponds. They were submersed but a lot of them grew to the point where a good portion of their stem was emersed and healthy as well. Photo at left is emersed growth like I see in a pond.
I have this plant in my ponds and one of my aquariums and I think it looks great. It quickly grows roots and looks good hanging over a waterfall. When I trim the emerged form in my ponds, it will branch off with many new stems, making it more dense and cover a greater area.
The image at top right is not M. aquaticum. The bottom right is, however. Color is golden yellow to green and can even get a hint of red/orange. The 'Information" indicates it's difficulty is "Hard" but it's actually very easy to take care of with no special requirements. Grows even in low light, and CO2 is not necessary. If the light is too low, the bottom leaves will fall off. It's necessary to add nutrients or it will stunt. This plant does not appear to be used very much in planted aquaria, but due to its large size (similar to M. mattogrossense or Limnophila aromatica), looks best in larger tanks. It's soft texture, like feathers, is quite unique compared to similar plants. Growth can be very fast in high light, added CO2, and fertilization. Expect more than 1" per day. It doesn't send out many side shoots so it doesn't get very bushy even when trimmed.