Plants

The four groups

Rhizome plants — Anubias, Microsorum, Bucephalandra

They grow from a horizontal rhizome and are tied or glued to wood and stone, never buried. Burying the rhizome kills them, slowly enough that most people do not connect cause and effect. They tolerate low light, need no CO2, and grow so slowly that a single new leaf a month is normal and healthy.

These are the plants to start with. They also collect algae precisely because they grow slowly — an Anubias leaf sits there for a year, and anything settling on it stays.

Rosette plants — Cryptocoryne, Echinodorus, Vallisneria

Rooted in the substrate, feeding mostly through their roots. Cryptocorynes are famous for melting: a few days after planting, every leaf dissolves. The plant is not dead. It is converting from emersed-grown leaves (how nurseries produce it) to submersed ones, and it regrows in two to four weeks. Do not pull it out. Almost everyone pulls it out.

Stem plants — Rotala, Ludwigia, Hygrophila

Fast, hungry, and the reason people buy CO2. They grow towards light, so they need trimming weekly once established, and every trim is also a propagation: the cut top is replanted and roots within days. Stems reward a tank with strong light, CO2 and consistent dosing; in a low-tech tank they stretch, go leggy and drop their lower leaves.

Carpeting plants — Hemianthus callitrichoides, Eleocharis, Glossostigma

The hardest group and the one most beginners attempt first, because carpets are what makes photographs look like photographs. They need high light reaching the substrate, CO2 in almost every case, and enough flow to keep detritus off them. A carpet that is not growing is a carpet that is dying.

Growth rate, light and CO2 at a glance

Group	Growth	Light	CO2	Attach
Rhizome	Very slow	Low is fine	Not needed	Tie to hardscape
Rosette	Slow to moderate	Low to medium	Optional	Root in substrate
Stem	Fast	Medium to high	Strongly advised	Push into substrate
Carpet	Moderate but demanding	High, at substrate level	Effectively required	Plant in small portions
Floating	Very fast	Any	Not needed	None — free floating

The plants sold as easy that are not

• Hemianthus callitrichoides — labelled beginner-friendly in every shop. Needs CO2, high light and patience. It is the single most common first-tank failure.
• Rotala macrandra — beautiful red, extremely fussy about nutrients and CO2 stability.
• Alternanthera reineckii — sold as an easy red; drops leaves at the first CO2 fluctuation.
• Any "aquarium plant" sold in a sealed tube that is actually a houseplant. Dracaena and Syngonium turn up in tubes regularly. They drown over about six weeks.

The genuinely forgiving ones nobody recommends

• Cryptocoryne wendtii — survives neglect, low light and no CO2. Melts once, then grows for years.
• Hygrophila polysperma — grows in almost anything, including tap water and bad light.
• Vallisneria — a wall of green from a few runners, provided the water is not too soft.
• Bucephalandra — slow, expensive, and almost impossible to kill.

Buying: what to look at

Prefer plants grown in vitro (in sealed cups) if you keep shrimp or want to avoid snails — they are pest-free by definition. Potted nursery plants are grown emersed and will melt back; that is normal, not a fault. Loose bunches held with a lead weight are the worst value: the weight crushes the stems it is wrapped around, and those stems rot.