Floating Plant Care

What floating plants actually do

It is worth understanding why they work, because it explains every care decision below. A floating plant sits at the surface with its leaves in open air and its roots dangling in the water. That position gives it three advantages nothing rooted can match.

• They pull nitrate and ammonia straight out of the water. Plants need nitrogen to grow, and the nitrogen in your tank is fish waste. A healthy raft of floaters competes directly with algae for that nutrient, which is why a well-planted tub stays clear with far less effort.
• They take carbon from the air, not the water. This is why they grow so fast without CO2 injection: carbon dioxide moves far more freely in air than in water, and their leaves are already in the atmosphere.
• They shade the surface. Less light in the water column means less algae, and in an outdoor tub in July it means cooler, more stable water.

The roots do a fourth job that matters if you are breeding anything: they grow biofilm, and biofilm is what newly hatched fry graze on before they are big enough for prepared food. My breeding guide covers that in more detail.

Which floating plant should you pick?

They all do the same core job, so choose on root length, growth speed, and how they look from above. Here is how the ones I grow compare.

Not sure? The variety pack is the practical answer for most people. Run all five for a season, see which thrives in your water and your light, then keep that one going.

Keeping them healthy

There is not much to it, and most failures come down to the same three things.

Still water

This is the big one. Floating plants hate having water splashed onto their leaves. A filter outflow hitting the surface will rot frogbit and water lettuce within days, and it is the most common reason people think they cannot grow floaters. Aim the outflow below the surface, baffle it, or run a gentle sponge filter instead. I use sponge filters in my own tubs, and as a bonus the fish tend to hang around the bubble column and play in it.

Light, but not necessarily much

Ordinary room light will keep frogbit and duckweed alive. Red Root Floaters need noticeably more to show their color, and Dwarf Water Lettuce prefers a brighter spot. Outdoors, natural daylight is more than enough for all of them, which is why they explode in a summer tub.

Nutrients

Floaters eat fish waste, so a well-stocked tank usually feeds them without help. If your leaves go pale yellow while new growth stays small, the tank is running lean, most often on iron. A general liquid plant fertiliser once a week fixes it. This is far more common in sparsely stocked indoor tanks than in outdoor tubs.

Why I include them with every fish or snail order

Every live animal order I ship goes out with a free assortment of floating plants, and it is not only a gift. In the bag they take up some of the ammonia that builds during transit. Once they arrive they carry on with that job in your tank or tub, and give a new setup a head start.

Which species you receive depends on what is thriving and what is legal to ship to your state. If you want a specific plant, or simply more of them, that is what the plant listings are for.

A note on shipping restrictions

Three of these are regulated in some states. Salvinia is prohibited in Texas and restricted in several other states, Dwarf Water Lettuce is on the noxious or prohibited lists of a number of states, and Amazon Frogbit is a listed noxious weed in California, Oregon, and Washington, so I cannot ship them everywhere. Giant Duckweed is native and Red Root Floaters are not on the state lists I checked, but rules change, so check your own state. Each listing shows the current restricted-state list, and if something is not legal where you live I simply pack more of the floaters that are, at no extra cost.

Wherever you keep them, never release aquarium plants into natural water. Compost the excess or pass it to another hobbyist instead.

Common questions