Dense Waterweed
Egeria densa
Also known as Brazilian Waterweed, Elodea, Anacharis
Plantae›Tracheophyta›Magnoliopsida›Alismatales›Hydrocharitaceae
📍 South America (widely naturalised)
Classic, bulletproof stem plant with whorls of bright green leaves. One of the best beginner plants — grows rapidly without CO2 and tolerates cool water. Also excellent for goldfish and temperate tanks.
Community Photos
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by @karleenmendoza
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Tanks keeping this 🌿
Growing in 4 tanksCommunity tanks featuring Dense Waterweed.
Compatible Livestock
Tolerates cool water and goldfish nibbling; provides shelter and oxygenation in goldfish tanks
Small, peaceful algae-eaters that won't damage plant structure and benefit from dense cover
Peaceful schooling fish that appreciate plant cover without uprooting or heavily grazing stems
Excellent companion plant with similar fast growth and low nutrient demands; creates dense planted areas
Harmless to plants; graze algae on leaves and provide bioload to support plant growth
Algae control without plant damage; nocturnal behavior minimizes competition for space
Common Diseases
Nutrient Deficiency
Yellowing leaves, stunted growth, pale coloration, leaf holes or transparent patches
Dose all-in-one fertilizer (e.g., Thrive, Flourish) 1-2 times weekly; ensure adequate macronutrients (nitrogen, phosphorus, potassium) and micronutrients (iron, boron, manganese)
Algae Overgrowth on Leaves
Green, brown, or black algae coating leaf surfaces; reduced photosynthesis and plant vigor
Increase water changes (25-30% weekly), reduce lighting duration to 8-10 hours daily, add algae-eating fish or shrimp, manually remove affected leaves
Stem Rot
Mushy, blackened stems; foul odor; leaves detaching easily from the stem
Remove affected stems immediately, improve water circulation with aeration, reduce organic waste buildup, perform 30-40% water change; ensure substrate is not compacted
Melting
Rapid leaf dissolution and transparency; plant appears to dissolve within days of planting
Acclimate plant slowly to new tank conditions over 1-2 weeks; ensure stable temperature (23-28°C), adequate lighting, and fertilization; this is usually temporary as the plant adjusts
Tips from the community 💡
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Quick Facts
- CO2
- not needed
- lighting
- low–medium
- maxHeight
- 50+ cm (19.5+ in)
- placement
- background
- substrate
- any
Water it likes
- ph
- 6.5–7.5
- hardness
- 3–15 dGH
- temperature
- 61–79°F (16–26°C)
Legality
No state or federal restrictions on record for this species.
Not legal advice, and possibly incomplete or out of date. Rules vary by state and locality and change over time — always confirm the current regulations with your state wildlife or agriculture agency before buying, keeping, or shipping this species.