Anacharis (Egeria Densa): The Complete Care & Growing Guide

Anacharis (Egeria densa), also called Brazilian Waterweed or Elodea, is one of the most popular and versatile aquarium plants in the hobby. Its bright green stems grow rapidly in almost any condition, making it a go-to choice for beginners, breeding tanks, and anyone who wants a plant that works hard from day one. Anacharis absorbs nutrients aggressively, outcompetes algae, and provides lush green coverage throughout your tank.

What Is Anacharis?

Anacharis is a fast-growing stem plant native to South America (Argentina, Brazil, Uruguay). Now found worldwide as a naturalized species, it thrives in freshwater lakes, ponds, and slow-moving streams. In the aquarium hobby, it's valued for its ease of care, rapid growth, and water-purifying abilities.

The plant features long, bright green stems with whorls of small, lance-shaped leaves. Stems can grow several feet long and branch freely, creating dense green thickets. Under good conditions, Anacharis produces small white flowers that reach above the water surface.

Why Anacharis Is Essential for Your Aquarium

• Aggressive nutrient absorption — One of the best plants for reducing nitrates, ammonia, and phosphates
• Natural algae fighter — Starves algae of nutrients through sheer growth speed
• Oxygenation powerhouse — Produces visible oxygen bubbles (pearling) under good light
• Versatile placement — Works floating, planted in substrate, or weighted in bunches
• Cold water tolerant — Thrives in unheated tanks and outdoor ponds
• Breeding essential — Dense stems protect fry and provide egg-laying sites

Anacharis Care Requirements

Lighting

Anacharis performs well under any lighting. In low light, stems grow taller and leggier, reaching toward the surface. Under moderate to high light, the plant produces denser foliage and may begin "pearling"—releasing visible streams of oxygen bubbles. For the best appearance, moderate light (30–50 PAR) produces compact, bushy growth.

Water Parameters

Anacharis prefers cooler water, making it perfect for goldfish tanks, unheated setups, and outdoor ponds. It tolerates tropical temperatures but grows best below 77°F. The plant handles both soft and hard water without issue and adapts to a wide pH range.

Substrate and Planting

Anacharis can be planted or left floating:

• Planted: Gently push the bottom 2–3 inches of each stem into substrate. Anacharis produces thin white roots from stem nodes that anchor in gravel or sand. Group 5–8 stems together for a fuller look.
• Floating: Let stems float freely at the surface. This is the easiest method and provides excellent surface cover and shade for fish below.
• Weighted bunches: Wrap the base of a stem bundle with a lead plant weight and place wherever you want in the tank.

How to Grow Anacharis Successfully

Initial Planting

When you receive Anacharis, it may look slightly wilted from shipping. This is normal. Rinse the stems in dechlorinated water and either float them or plant immediately. New growth adapted to your tank conditions will appear within a week. Don't be alarmed if some lower leaves yellow and drop during the first week—the plant is adjusting.

Maintenance and Trimming

Anacharis grows fast enough that regular trimming is essential:

1. Trim stems when they reach the water surface or become too tall
2. Cut just above a leaf node using sharp scissors
3. Replant the cuttings (each becomes a new plant) or discard
4. Remove yellowing lower portions of stems—they won't recover
5. Thin out dense growth periodically to maintain water flow

Fertilization

In a tank with fish, Anacharis rarely needs additional fertilization—it feeds on fish waste. In lightly stocked or shrimp-only tanks, a weekly dose of all-in-one liquid fertilizer keeps it growing vigorously. If you notice pale or yellowing leaves, iron supplementation usually solves the issue.

Anacharis in Different Tank Setups

Goldfish Tanks

Anacharis is one of the few plants that can survive (and thrive) with goldfish. While goldfish will nibble on it, the plant grows fast enough to stay ahead of the damage. Its cold-water preference perfectly matches goldfish temperature requirements (65–72°F).

Community Tropical Tanks

Use Anacharis as a background plant, creating a green wall behind smaller foreground species. Its bright color contrasts nicely with darker plants like Anubias and Java Fern.

Breeding Tanks

Dense floating Anacharis gives fry immediate protection. Egg-scattering species deposit eggs on the fine leaves, and the thick growth prevents adult fish from finding and eating them. It's a staple in livebearer and tetra breeding setups.

Shrimp Tanks

Anacharis provides biofilm-covered surfaces for shrimp to graze on and hides baby shrimp effectively. Its fast nutrient uptake helps maintain the clean water that shrimp need.

Propagation

Anacharis is one of the easiest plants to propagate:

1. Stem cuttings: Cut any stem into sections at least 4–5 inches long. Each piece grows into a new plant.
2. Side shoots: The plant produces lateral branches naturally. Separate these and plant individually.
3. Tip cuttings: Cut the growing tip (top 6 inches) and replant. This also encourages the original stem to branch.

With Anacharis, propagation is less of a technique and more of an inevitability. You'll be sharing extras with friends within weeks.

Common Problems and Solutions

Melting or Disintegrating

Usually happens when Anacharis is moved from cool water to warm water (or vice versa) too quickly. Acclimate gradually by floating the plant in a bag for 30 minutes before releasing. If melting occurs, remove affected portions and let the healthy sections recover—new growth typically appears within a week.

Yellowing Leaves

Indicates nutrient deficiency (usually iron) or insufficient light. Increase your light duration to 8 hours minimum and add an iron-containing fertilizer. In well-stocked fish tanks, yellowing is less common because fish waste provides ample nutrients.

Leggy, Sparse Growth

Caused by low light. The plant stretches toward the surface, producing fewer leaves per stem length. Increase light intensity or duration. Regular topping (cutting the top and replanting) also forces bushier growth lower on the stem.

Floating Debris from Leaf Shedding

Normal during acclimation. Old leaves adapted to the previous environment fall off as new leaves suited to your tank grow in. Siphon fallen leaves during water changes. Shedding should stop after 1–2 weeks.

Anacharis vs. Similar Plants

Frequently Asked Questions

Can Anacharis grow in low light?

Yes. Anacharis survives in low light but grows slower and becomes leggy. For the densest, most attractive growth, provide at least moderate lighting. It's still a great choice for low-light setups—just expect taller, sparser stems.

Is Anacharis safe for goldfish?

Absolutely. Anacharis is one of the top recommended plants for goldfish tanks. It tolerates cool water, grows fast enough to survive goldfish nibbling, and helps absorb the heavy waste that goldfish produce.

Does Anacharis need CO2?

No. Anacharis grows well without CO2 supplementation. Adding CO2 will supercharge growth and produce a more vibrant, compact plant, but it's completely unnecessary for healthy growth.

Why is my Anacharis melting?

Most commonly caused by a sudden change in water parameters (temperature, pH, or hardness) or shipping stress. Remove melted portions, leave the healthy parts, and new adapted growth will emerge within 1–2 weeks.

Can Anacharis be used in outdoor ponds?

Yes, and it's excellent for ponds. Anacharis tolerates temperatures down to 50°F, controls algae naturally, provides fish cover, and oxygenates pond water. In warmer climates, be aware it can become invasive—contain it in pots or harvest regularly.

How fast does Anacharis grow?

Under moderate light without CO2, expect 2–3 inches per week. With CO2 and high light, growth can exceed 4 inches per week. It's one of the fastest-growing aquarium plants available.

Related Aquarium Plant Guides

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• Floating Aquarium Plants — Anacharis can float — learn about more floating species
• Aquarium Plants That Grow in Gravel — Anacharis grows in gravel — more hardy substrate species