How to Grow Water Soldiers: Step-by-Step for Aquatic Cultures

If you searched 'how to grow water soldiers,' you could mean one of three very different things: the aquatic plant Stratiotes aloides (also called water soldier or water aloe), mosquito larvae (which some hobbyists and fish keepers call 'water soldiers' as a colloquial term for live fish food), or brine shrimp (Artemia), another popular live feed sometimes lumped into the 'water creatures you culture at home' category. Each one needs a completely different setup, so picking the right organism first saves you a lot of wasted effort.

Which 'water soldier' do you actually mean?

Stratiotes aloides is a true aquatic plant. It looks like a spiky rosette of stiff, serrated leaves and spends most of the year submerged, then blank" rel="noopener noreferrer">floats to the surface in summer to flower. It's a popular pond and aquarium plant in Europe and has become invasive in parts of North America after hobbyists released it into the wild, so check your local regulations before growing it outdoors. It needs no salt, tolerates depths up to 5 meters, and reproduces by producing offsets (daughter plants) from runners. To grow gummy bears in water, you generally need to control the water temperature, use the right container, and let the gelatin-like candy swell and set properly.

Mosquito larvae are the wriggly, comma-shaped creatures you find in standing water. Many aquarists and fish breeders deliberately culture them as a high-protein live food for small fish, amphibians, and invertebrates. They don't need salt, they need warmth, and they develop from egg to adult in roughly 7 to 10 days at room temperature, so harvesting on time is critical or you'll end up releasing adult mosquitoes.

Brine shrimp (Artemia) are the classic 'sea monkeys' of the aquaculture world. They hatch from dry cysts in saltwater, grow to a harvestable nauplii stage in about 24 hours, and are the most widely cultured live feed in home aquariums. They need saline water, aeration, and warmth. This guide covers all three, but it focuses most heavily on the two you're most likely growing as live fish food: mosquito larvae and brine shrimp. If you want the quick answer for how to grow marimo balls, focus on their specific light, temperature, and daily care needs rather than pond or aquarium setups for other “water soldiers.”.

Choosing your grow setup and dialing in water parameters

Growing Stratiotes aloides (the plant)

A garden pond at least 60 cm deep works best. You can also use a large tub or barrel pond with a minimum capacity of around 100 liters. Stratiotes doesn't need a substrate because it floats or suspends freely, drawing nutrients directly from the water column. Aim for neutral to slightly alkaline freshwater: pH 7.0 to 8.0, temperatures between 5°C and 25°C (it tolerates cold winters well), and good water quality with low nutrient inputs. It actually helps clear water by competing with algae for nutrients, which makes it a useful plant in a balanced pond system. In North America, keep it in a fully enclosed, controlled container and never release it outdoors.

Culturing mosquito larvae

A simple plastic tub, bucket, or shallow container works fine, 10 to 20 liters is a practical starting size. Use dechlorinated or aged freshwater. No filtration, no salt, and no aeration needed (larvae breathe through a surface siphon, so still water suits them perfectly). Keep the temperature between 20°C and 30°C for reliable development. A warmer room speeds things up considerably: at 28 to 32°C larvae can reach harvest size in as few as 4 to 6 days, while cooler temperatures of 15 to 20°C can extend development to 2 weeks or more. Important: cover your culture with a fine mesh or screen at all times to prevent adults from escaping. This is not optional.

Hatching and culturing brine shrimp (Artemia)

A 1 to 2 liter plastic bottle or a dedicated conical hatching vessel is the standard starting point for nauplii production. For grow-out to adult brine shrimp, scale up to a 20 to 40 liter aquarium or food-grade tub. Salt the water to 25 to 35 g/L (standard marine salt mix works fine), target a pH of 8.0 or above and maintain it by adding 0.5 g of sodium bicarbonate per liter of culture water. Temperature should sit between 26°C and 29°C (don't exceed 30°C, or hatch rates fall sharply). Heavy aeration is non-negotiable for Artemia; they need well-oxygenated water at all times.

Where to get your starting stock and how to introduce it

Stratiotes aloides

Source plants from specialist aquatic nurseries or water garden suppliers, ideally ones that clearly state the plants are from a contained, non-wild population. In the US, confirm the species is legal in your state before ordering. Once you have a plant, place it in your pond or tub with no substrate planting required. It will produce offset rosettes from horizontal runners. Once offsets reach 5 to 10 cm across, you can detach them and transfer to a second container to expand your collection.

Mosquito larvae

You have two options: let wild mosquitoes lay eggs in your outdoor container naturally, or transfer a batch of larvae from an existing outdoor source (a rain barrel, neglected bucket, or garden pond). The natural method is simpler for most people. Set up a tub outdoors in a warm spot, fill it with dechlorinated water, add a pinch of dry yeast or a small amount of hay-infused water to attract egg-laying females, and check after 2 to 3 days.

Once egg rafts appear (they look like tiny floating grey-brown specks), bring the container indoors if you want to control conditions. For a contained indoor culture where you're breeding from adults, target around 200 to 300 larvae per 10 liters as a starting density. Any denser than that without good feeding management and you'll see die-offs fast.

Brine shrimp (Artemia)

Buy dried Artemia cysts from an aquarium supplier. Quality matters here: cheap cysts often have low hatch rates. Add cysts at roughly 1 to 2 grams per liter of prepared salt water. For a 1-liter hatch bottle, that's about 1 to 2 grams, or roughly a quarter teaspoon. If you're scaling to batch culture in a 20-liter tank, FAO guidance suggests inoculation densities up to about 5,000 larvae per liter for basic batch culture are manageable without serious survival interference. After stocking, check nauplii density the following morning by sampling a small volume and counting under a light source. Adjust next batches based on what you see.

Feeding plan: what to feed, how much, and when

Mosquito larvae feeding

Mosquito larvae are filter feeders and detritivores. They eat microorganisms, algae, and organic particles suspended in the water. In practice, a pinch of powdered spirulina, dried yeast, or finely ground fish food added to the culture water every 1 to 2 days is enough. The trap most beginners fall into is overfeeding: if the water turns dark grey or smells bad within a day, you've added too much. Aim for a light green or slight tan tint to the water. I made the mistake of adding too much yeast to my first batch and lost half the larvae to bacterial bloom within 3 days. Less is genuinely more here.

• Feed once every 1 to 2 days with a small pinch of powdered spirulina, dried yeast, or fine fish meal
• Water should stay lightly tinted, not murky or dark
• If it smells foul, skip feeding for a day and do a partial water change
• Avoid liquid fertilizers, manure teas, or large particles that sink and rot

Brine shrimp feeding

Nauplii (newly hatched brine shrimp) don't need to be fed for the first 24 to 48 hours because they still carry their yolk sac. If you're growing them beyond nauplii stage to juvenile or adult size, feed unicellular algae like Nannochloropsis or Spirulina powder, or a dedicated Artemia diet product. Feed in small amounts twice daily, targeting water that looks lightly green-tinted. Overturn any excess uneaten food by doing a small water change if the water starts to cloud heavily.

Stratiotes aloides as a living plant doesn't require feeding at all; it absorbs nutrients directly from the water column. To make jelly balls that grow in water, you need the right jelly bead type, plus clean water, correct soaking time, and safe handling so they expand as intended how to make jelly balls that grow in water.

Aeration, filtration, temperature, and light

These three organisms have almost opposite needs when it comes to aeration and filtration, which is worth understanding clearly before you set anything up. Water beads can be used as a growing medium, so you would follow similar hydration and container setup principles.

For Artemia, light plays a useful practical role beyond just growth: brine shrimp nauplii are positively phototactic, meaning they swim toward light. When harvesting, you can shade the top of the hatch vessel and shine a light at the bottom to concentrate the nauplii in one spot for easy collection with a fine pipette or baster. At around 2,000 lux during the hatching phase, you'll also see better hatch rates. For mosquito larvae, a dark or shaded environment actually reduces predation stress if you're in an outdoor setup, but indoors with no natural predators, light level isn't critical.

Day-to-day maintenance and harvesting

Mosquito larvae: timing is everything

The entire egg-to-adult cycle for Culex mosquitoes is about 7 to 10 days at typical room temperatures. Harvest larvae at days 3 to 6, when they're in the L3 to L4 larval stage and at their largest before pupation. Once you see comma-shaped pupae (tumblers), harvest immediately or separate them out, because adults can emerge within 24 to 48 hours of pupation. Use a fine net or baster to scoop larvae out and feed directly to fish.

For a continuous supply, stagger your tubs so a new batch is started every 3 to 4 days. Change out roughly 30 to 50 percent of the culture water every 3 to 4 days and replace with fresh dechlorinated water to keep organic buildup from crashing the batch.

Brine shrimp: batch vs. continuous culture

For most home setups, batch culture is the simplest approach. Hatch a new bottle every 24 to 48 hours so you always have a fresh supply of nauplii ready. Harvest by turning off aeration, waiting 5 minutes for empty shells and unhatched cysts to separate, then shining a light at the bottom of the vessel to concentrate live nauplii. Pour through a fine brine shrimp net, rinse with clean saltwater, and feed.

For grow-out to adult size, maintain the culture in a 20 to 40 liter tank with continuous aeration, feed twice daily, do 20 percent water changes every 2 to 3 days, and harvest adults with a net when the population looks dense (typically 7 to 14 days after hatching). Keep culture vessels clean by rinsing with a dilute bleach solution between batches and rinsing thoroughly before reuse; this prevents fungal and bacterial buildup that kills subsequent hatches.

Stratiotes aloides: managing growth and spread

This plant grows steadily through spring and summer, producing new offsets regularly once established. If you meant the plant, focus on maintaining the right pH, temperature, and water quality so your water soldier can increase its offsets and overall growth. Remove excess rosettes by simply pulling them off the runner. If you're in an indoor closed system, thin the plant to prevent it from shading the entire water surface. Do a 25 to 30 percent water change monthly in enclosed setups, and monitor for snail infestations, which love the dense leaf structure.

When things go wrong: troubleshooting common problems

Die-offs

Sudden die-offs in mosquito larvae are almost always caused by one of three things: water fouling from overfeeding, a temperature crash, or overcrowding. Check your water quality first: if it smells bad or looks dark, do an immediate 50 percent water change, cut feeding for 2 days, and reduce density by splitting the culture into two containers. For Artemia, die-offs usually mean oxygen crash (check your aeration), pH drop below 7.5 (add a pinch of sodium bicarbonate), or salinity that's drifted too high from evaporation (top up with fresh water, not salt water, to compensate for evaporation losses).

Poor growth or slow development

For mosquito larvae, slow development almost always points to temperature. If your room is below 20°C, development can stretch to 2 weeks and feeding efficiency drops significantly. Move the culture to a warmer spot or use a low-watt aquarium heater set to 26 to 28°C. For Artemia, poor hatch rates are usually a cyst quality issue or a pH problem. Test pH first (it should be above 8.0) and try a new batch of cysts from a different supplier before assuming your setup is wrong.

Cloudy or stagnant water

Light cloudiness in a mosquito larva culture is normal and indicates microbial activity, which is your larvae's food source. Heavy, dark cloudiness with a bad smell is bacterial bloom. Fix it with an immediate 50 percent water change and a feeding pause. For Artemia, heavy cloudiness in a grow-out tank means overfeeding or insufficient aeration. Increase airflow and cut back feeding volume by half for a few days. For Stratiotes in a pond, cloudy water usually resolves on its own once the plant establishes, since it actively competes with algae for nutrients.

Contamination and cross-contamination

If you're running multiple mosquito species or strains for research or comparison purposes, keep equipment strictly separated between cultures, because cross-contamination between strains is very difficult to detect and can ruin results. Standard lab protocol recommends cleaning hatch vessels with dilute bleach (10 percent solution, 10-minute contact time) followed by thorough rinsing before reuse. For home hobbyists culturing a single species for fish food, the risk is lower, but rinsing equipment between batches still prevents fungal and bacterial carryover that reduces hatch success over time.

Escape (mosquito adults)

If you find adult mosquitoes in your home and you're running a larval culture, your cover mesh has a gap. Audit every seam and seal with tape immediately. Harvest all cultures and check for pupae. Adults can emerge faster than you expect, especially in a warm room in summer. A mesh with openings smaller than 1 mm is sufficient to prevent adult escape.

Your action plan in short

1. Decide which organism you're actually growing: Stratiotes aloides (the aquatic plant), mosquito larvae (freshwater live food), or Artemia (saltwater live food).
2. Set up the right container: a mesh-covered tub for mosquito larvae, a conical bottle or aerated tank with salt water for Artemia, or a pond/tub with clean freshwater for Stratiotes.
3. Get your water parameters right before you add any stock: pH 7.5 to 8.0, correct temperature, and for Artemia, salinity at 25 to 35 g/L with bicarbonate buffer.
4. Source clean starting stock: wild egg collection or purchased larvae for mosquitoes, high-quality cysts for Artemia, or nursery-grown plants for Stratiotes.
5. Feed lightly and consistently: powdered yeast or spirulina every 1 to 2 days for mosquito larvae; algae or dedicated feed twice daily for grow-out Artemia.
6. Harvest on time: mosquito larvae at days 3 to 6, Artemia nauplii at 24 hours, adult Artemia at 7 to 14 days, Stratiotes offsets when they reach 5 to 10 cm.
7. If something goes wrong, check water quality first, then temperature, then density. Most failures trace back to one of those three factors.