Plant deficiency ID
Why does your plant look like that?
Yellow old leaves, pale new tips, pinholes, twisted growth, fading reds. Each one points at a different nutrient. The first question is always where the damage shows, on the old leaves or the new, so start there and narrow it down.
Older, lower leaves first
Mobile nutrients get pulled from old leaves to feed new growth, so a shortage shows on the lower, older leaves first.
- Nitrogen DeficiencyOlder, lower leaves fade to pale yellow evenly and go see-through, while the tips stay green.
- Phosphorus DeficiencyOlder leaves darken with purple or bronze tints, and green spot algae creeps onto the glass and slow leaves.
- Potassium DeficiencySmall pinholes in the leaves, often ringed with yellow, on older and middle-aged growth.
- Magnesium DeficiencyOlder leaves yellow between the veins while the veins stay green.
New growth at the tips first
Immobile nutrients can't be moved once placed, so the newest leaves and growing tips show the shortage first.
Across the whole plant
Not a mineral shortage, but the most common limit on plant growth, and it slows and shrinks the whole tank.
A deficiency is the plant telling you what the water is short of. Work out where the damage starts, match it to a nutrient, then fix the supply rather than trimming symptoms. Each guide links to plants that show the shortage early, so you can compare against a species you keep. If the trouble is something growing on the leaf or glass rather than the leaf itself, that is algae, see algae ID.