Aquarium plants: care basics for beginners
Light, CO₂, fertiliser — the three pillars of a planted tank. What you need for a healthy green balance.
A planted tank is a system of three interlocked factors: light, CO₂, and fertilisers. Tip any of them out of balance and algae move in. This guide is the foundation.
The three pillars of a planted tank
1. Light
LED fixture at 6500–7500 K colour temperature, about 0.5 W per litre — a starter setup for most plants. Photoperiod: 6–8 hours per day, no longer. Longer triggers algae.
2. CO₂
Plants build tissue from carbon. Without CO₂ injection, levels sit at 2–5 mg/L — enough only for hardy species (anubias, fern, vallisneria). Demanding plants need 20–30 mg/L from a pressurised system.
3. Fertilisers
• Root tabs — pushed into the substrate under larger plants (echinodorus, cryptocoryne). • Liquid all-in-one (K, Mg, Fe, micros) — daily or 2–3× weekly. • Nitrates and phosphates — in heavily planted tanks they can run out and need dedicated dosing (PPS-Pro, EI).
Beginner-friendly plants
A bulletproof starter set: anubias nana (tied to driftwood), Java fern (also epiphyte), vallisneria (background), Cryptocoryne wendtii (midground). All four tolerate low light and need no CO₂.
Trouble signals
• Plants 'melt' right after planting — normal for 2–3 weeks (adaptation). After that, check light and water parameters. • Yellow leaves — iron or nitrogen deficiency. • Pinholes in leaves — potassium deficiency. • Black spots on leaves — algae, often a symptom of wrong light/CO₂ ratio.
What to avoid
Don't plant in tanks with goldfish or large cichlids — they'll uproot or eat everything. Avoid 'lucky bamboo' and 'dracaena' from pet stores — these are terrestrial plants and die underwater within a month.
There's no 'algae cure' in a planted tank. There's only the balance of light, CO₂, and fertiliser — plus regular water changes.
FAQ
- Can I grow red plants without CO₂?
- Tough. Most red species (ludwigia, alternanthera, rotala) need CO₂ to develop their red pigment. Without it they shift to green-brown.
- How often should I do water changes in a planted tank?
- 20–30 % weekly is the rule for most setups. High-tech tanks running EI dosing can do up to 50 % weekly to flush excess fertiliser.
Goldie editorial team
Practising aquarists with a combined 30+ years of experience · Biologists and editors, fact-checking against FishBase and Seriously Fish · Every piece is reviewed by a qualified ichthyologist before publication
Veterinary ichthyologist, specialist in aquarium fish diseases
DVM in veterinary medicine, University of Milan · PhD in hydrobiology, specialising in ornamental fish diseases · 10+ years of private veterinary practice with aquatic species
Sources
- Tropica — Easy plants · Tropica · 2026-05-22
- Practical Fishkeeping — Planted tank guide · Practical Fishkeeping · 2026-05-22