Red Root Floater Care Guide: Getting the Red, Stopping the Melt

Phyllanthus fluitans is the only common floating plant that produces real red colour rather than green. Coin-sized round leaves sit flat on the surface, trailing crimson roots into the water column below.

It is also the floater most likely to arrive healthy and then dissolve within a fortnight — almost always for one avoidable reason.

Water on the leaves is what kills it

This is the whole game with Red Root Floater, and it catches out people who grow every other floating plant successfully.

The leaves are water-repellent on top and are meant to stay dry. When droplets sit on them — from filter spray, an air stone, a spray bar breaking the surface, or condensation dripping off a lid — the affected leaves yellow, go translucent and rot. The rot spreads through the cluster.

Two fixes, and you generally need both:

Calm the surface. Aim filter outflow below the waterline rather than across it. If you run an air stone, move it or reduce it. Some surface movement is fine; spray and splashing are not.

Leave an air gap under the lid. A tightly sealed lid collects condensation and drips it straight back onto the leaves, which does exactly the same damage as spray. A partially open lid or a raised light usually solves it.

If your floater is melting, check these before you touch anything else. Nutrients and lighting are rarely the cause.

Why it is green instead of red

Red Root Floater is green under moderate light and red under strong light. A green plant is not a sick plant — the colour is a lighting response, not a health indicator.

Because it floats, it sits closer to the light than anything else in the tank, so it colours up at lower fixture settings than a substrate plant would need. If it is still green under strong light, the usual missing ingredient is iron. Dose a micronutrient fertiliser containing iron and give it two to three weeks.

Lean nitrate also helps push the red. A heavily fed tank tends to produce large green leaves; a leaner one produces smaller, deeper red ones.

It grows fast, and that is a management problem

Under good conditions this plant roughly doubles its coverage every week or two. Left alone it will carpet the entire surface, and a solid mat of floaters cuts light to everything beneath it.

Thin it by hand every week or two. Scoop out a third to a half and discard or share it. Keeping roughly half to two-thirds of the surface open is a reasonable target for a planted tank.

That fast growth is also useful. It strips nitrate and phosphate directly from the water column, which is exactly what algae wants, so a well-managed patch is a genuine algae control tool.

Shrimp and fry

The trailing red roots are one of the best surfaces in the hobby for shrimp. They collect biofilm, shrimplets graze them constantly, and they give cover at the surface where most tanks offer none.

Fry use them the same way. If you are breeding at the surface, a patch of Red Root Floater does more than any commercial spawning mop.

Introducing a new portion

Float it, and do nothing else. There is no planting and no attaching.

Some leaves usually look poor for the first week after shipping, since the plant has spent a couple of days in a sealed bag with its leaves wet. Remove any that go soft or translucent so the rot does not spread, and let the healthy clusters recover. New growth appears quickly once surface conditions are right.

Quick reference

• Light — Medium to high; strong light for red colour
• CO2 — Not required
• Water — 72–82°F, pH 6.0–7.5
• Feeding — Water column; iron for colour
• Surface — Still, with an air gap under the lid
• Propagation — Runners, very fast
• Difficulty — Intermediate

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