Why Did My Frogbit Die?

That's only going to happen if there aren't enough nutrients in the water column for the floating plant to absorb. And if that's the case, more can easily be added. jsuereth said: If your plants in the tank become well established, they can kill off floating plants in the tank.

Does Frogbit die off in winter?

Frog-bit undergoes a natural die-off at the end of the season in which the plant dies and sinks to the bottom of the water. This is of particular concern because the dead matter lowers the dissolved oxygen concentration of the water, putting other organisms at risk of dying.

Why did my floating plants die?

This is likely a nitrogen deficiency. The old leaves are turning yellow and dying but the new leaves are green and solid. The new leaves are also smaller than old leaves which means the nitrogen deficiency has progressed quite far and is in the advanced stage right now.