Fertilising is the easiest way to keep aquarium plants lush and green — but how often should you actually do it? Here’s a simple, low-tech-friendly answer.
Quick answer: For most low-tech tanks, dose a liquid all-in-one fertiliser once a week, right after your weekly water change, following the bottle’s rate for your tank volume. Add root tabs in the substrate for heavy root-feeders like Cryptocoryne and swords. Yellowing or translucent leaves, stalled growth, or small holes in leaves are signs plants need feeding — but do not overdose, because excess nutrients feed algae instead.
The simple rule
For most low-tech tanks, dose a liquid all-in-one fertiliser once a week, right after your weekly water change. Follow the bottle’s dosing for your tank volume.
Signs your plants need feeding
- Yellowing or translucent leaves (often nitrogen, potassium or iron).
- Slow or stalled growth.
- Small holes or pale new leaves.
Don’t overdo it
More isn’t better — excess nutrients feed algae. Stick to a consistent weekly schedule, and for heavy root-feeders like Cryptocoryne and swords, add root tabs in the substrate.
How often to fertilise, by tank type
| Tank type | Liquid fertiliser | Root tabs |
|---|---|---|
| Low-tech, only epiphytes (Anubias, Java fern, Buce, moss) | Once a week at half to full dose | Not needed |
| Low-tech mixed tank with stems and Crypts | Once a week at full dose | Every 2–3 months near Crypts and swords |
| Tank with CO₂ and strong light | 2–3 times a week (or daily small doses) | Every 1–2 months |
| Heavily planted with floating plants | Once or twice a week | Only for rooted plants |
| Shrimp tank | Once a week at a reduced, shrimp-safe dose | Rarely; avoid disturbing the substrate |
Liquid fertiliser vs root tabs: which do you need?
Epiphytes feed from the water, rooted plants feed from the substrate. Anubias, Java fern, Bucephalandra, mosses and floating plants take nutrients through their leaves and roots in the water column, so a liquid fertiliser is all they need. Cryptocoryne, Amazon swords and Vallisneria send roots deep into the substrate, so they grow much better with root tabs pushed in near their base. Most mixed tanks benefit from both.
A simple weekly routine
- Do your weekly 25–30% water change.
- Dose liquid fertiliser for the full tank volume straight after the water change.
- Check new leaves once a week; pale or holey new growth means it is time to increase the dose slightly.
- If algae appears, reduce light hours before you reduce fertiliser.
Reading nutrient deficiencies
- Old leaves turning yellow: usually nitrogen shortage.
- Pinholes in older leaves (common on Anubias and Java fern): potassium shortage.
- Pale or white new leaves with green veins: iron shortage.
- Twisted or stunted new growth: calcium or trace-element shortage, common in very soft RO water.
Frequently asked questions
Do Anubias and Java fern need fertiliser?
They survive without it, but a weekly liquid fertiliser keeps leaves dark green and prevents pinholes and brown patches, especially in tanks with few fish.
Can fertiliser harm fish or shrimp?
Plant fertilisers dosed at the recommended rate are safe for fish. Shrimp are more sensitive to copper and overdosing, so start with a reduced dose in shrimp tanks.
Should I fertilise before or after a water change?
After. Dosing right after a water change means nutrients are not immediately removed, and plants get a full week of feeding.
Keep your plants thriving with our aquarium plant fertilizers — delivered across India.
For the full breakdown of what to dose and why, see our NPK and micronutrients dosing guide.
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