Seachem Flourish vs NilocG Thrive: Which Liquid Fertilizer Does Your Tank Need?
Seachem Flourish and NilocG Thrive compared on what each contains, dosing, nitrogen and phosphorus, shrimp statements, and which tanks each suits.
These two are often compared as "all-in-one" liquids, but only one of them is. NilocG Thrive is an all-in-one liquid with macro and micronutrients, including nitrogen, phosphorus, and potassium. Seachem Flourish is a comprehensive supplement of calcium, magnesium, iron, and trace elements with no significant nitrogen or phosphorus. If you want one bottle to cover N, P, K, and traces, Thrive is built for that. If your tank already gets nitrogen and phosphorus from fish waste, root tabs, or separate macros, Flourish adds the trace elements. On shrimp, Seachem states Flourish is safe for invertebrates at recommended doses. NilocG's product page makes no explicit livestock safety statement, and NilocG sells a separate shrimp version, Thrive S.
What we compared
Both are liquid fertilizers dosed into the water column of a planted tank. We compared them on:
- What is in the bottle. Macronutrients, iron, and trace elements.
- Dosing basis. How much to add, for how much water, and how often.
- Livestock statements. What each maker says about shrimp and invertebrates.
- Fit with the rest of your routine. Fish load, root tabs, and other fertilizers.
- Handling and storage. Dispensing and storage instructions from the makers.
All details come from the manufacturers' product pages, listed under Sources. We have not tested either fertilizer hands-on.
Side by side
| Product | Fits | Best for | Skip if |
|---|---|---|---|
 Seachem Flourish (250 mL / 8.5 fl oz)Model Flourish | low-tech tanks, CO2 tanks | A low-tech or CO2 tank that needs a trace-element supplement alongside root tabs or macros. | You already dose an all-in-one fertilizer that covers trace elements. |
 NilocG Aquatics Thrive All-in-One Liquid Aquarium Plant Fertilizer (500 mL / 16.9 oz)Model Thrive | low-tech tanks, CO2 tanks | A planted tank keeper who wants a single all-in-one liquid fertilizer. | You keep a dedicated shrimp tank and would rather use the maker's shrimp-specific formula. |
| Detail | Seachem Flourish (250 mL) | NilocG Thrive (500 mL) |
|---|---|---|
| Type | Comprehensive liquid supplement for the planted aquarium | All-in-one liquid fertilizer (macro and micronutrients) |
| Nitrogen and phosphorus | No significant levels | N 2.56%, P2O5 1.58% |
| Potassium | Not stated on Seachem's product page | K2O 9.7% |
| Iron and traces | Calcium, magnesium, iron, and trace elements (boron, cobalt, copper, manganese, molybdenum, zinc) | Mg 0.32%, S 0.54%, Fe 0.42%, Mn 0.168%, B 0.008%, Zn 0.0038%, Mo 0.0006%, Cu 0.0002% |
| Copper | 0.0001% | 0.0002% |
| Dose | 1 capful (5 mL) per 250 L (60 US gal), once or twice a week | 1 mL per 5 US gal, 1-3 times per week depending on lighting and plant demand |
| Shrimp statement | Seachem states it is safe for invertebrates such as shrimp at recommended doses | No explicit livestock safety statement on the product page; a separate shrimp formula, Thrive S, exists |
| Storage and dispensing | Refrigeration recommended 3 months after opening | Easy-Dose cap |
| Sizes offered | 50 mL, 100 mL, 250 mL, 500 mL, 2 L, 4 L | 500 mL, 2,000 mL refill, 4,000 mL refill |
Dosing basis is different
The two makers state doses on different bases, so do not swap one product's dose into the other. Seachem doses Flourish by the capful per 250 L (60 US gal). NilocG doses Thrive per 5 US gal, with frequency set by light: NilocG suggests 1-2 doses per week for low-light tanks and 3 per week for high-light systems. Always measure your actual water volume, which is less than the tank's nominal size once substrate and hardscape are in.
Choose Seachem Flourish if
- Your tank already gets nitrogen and phosphorus. In a stocked low-tech tank, fish waste often supplies some, and root tabs feed heavy root feeders. Flourish then fills in the iron and trace elements.
- You dose macros separately. If you already add nitrogen, phosphorus, or potassium on their own, Flourish covers the micros without adding more N or P.
- You keep shrimp and want a maker's statement. Seachem states Flourish is safe for invertebrates such as shrimp at recommended doses.
- You want a small bottle. Flourish is offered from 50 mL up.
Choose NilocG Thrive if
- You want one bottle for everything. Thrive covers nitrogen, phosphorus, potassium, iron, and trace elements together.
- Your tank is lightly stocked or high-light. Plants in these tanks can run short of nitrogen and phosphorus, which a micro-only supplement does not provide.
- You want dosing scaled to light. NilocG gives low-light and high-light frequencies.
- You prefer a metered cap. Thrive uses an Easy-Dose cap.
When neither is right
- You keep a dedicated shrimp tank and want Thrive's convenience. NilocG makes a separate shrimp-specific formula, Thrive S; the standard Thrive page has no explicit livestock safety statement.
- You want to adjust each nutrient separately. Thrive's ratio is fixed. Separate products, such as single-nutrient supplements, give more control. See our fertilizer picks.
- Your plants are mostly heavy root feeders. Swords and crypts take much of their food from the substrate. Root tabs may matter more than either liquid; our fertilizer basics guide explains the split.
- Your heavily stocked tank already runs high nitrate. Thrive contains nitrogen and phosphate on top of what fish waste already adds. Test nitrate before adding more, and consider a micro-only supplement instead.
Compatibility and maintenance differences
Nitrate and phosphate. Thrive adds both, so check nitrate with a test kit when you start dosing, especially in a heavily stocked tank. Flourish adds no significant amounts of either, so a tank dosed only with Flourish relies on fish waste, root tabs, or other products for them.
Storage. Seachem recommends refrigerating Flourish 3 months after opening. NilocG's product page gives no storage instruction for Thrive; follow the label.
Algae. Dosing more than plants can use, with either product, can feed algae. Start at the low end of the maker's dose and adjust by plant response. Our algae troubleshooting guide covers balancing light, CO2, and nutrients.
How we chose
- Frequently compared, but different jobs. Buyers often weigh these two as their first liquid fertilizer, so we set out what each actually contains.
- Specifications and statements from the manufacturers' product pages, listed in the sources. Shrimp statements are reported exactly as each maker states them.
- Identity confirmed against the retail listing for each exact size.
- Research-based. We have not tested these fertilizers hands-on. There are no scores or rankings, and the right choice depends on what your tank already supplies.
Related guidance
Sources
- Seachem Flourish product page, Seachem
- NilocG Thrive All-in-One Liquid Aquarium Plant Fertilizer product page, NilocG Aquatics
This page is research-based: we have not tested the equipment or methods ourselves. It draws on the sources listed and established hobby practice.
Keep reading
Planted Tank Fertilizer Basics
What macro and micronutrients do, liquid fertilizers versus root tabs, how to dose for your real water volume, and how to read plant symptoms without overreacting.
Best Fertilizers for Planted Aquariums, by Need (2026)
All-in-one liquids, single-nutrient supplements, root tabs, and a carbon supplement for planted tanks, matched to what your tank actually lacks.
Keeping Shrimp in Planted Tanks
How to keep Neocaridina and Caridina dwarf shrimp with live plants: water parameters, copper risk, aquasoil, filter safety, acclimation, and fertilizer cautions.