Comparison: Best The Fish Fertilizer (Updated | Dec 1st)
If your garden’s looking a little under the weather, the fix might just come from the sea. But with so many options out there, how do you know which one’s truly the best? We’ve dug into the top contenders, testing for effectiveness, ease of use, and value, so you don’t have to guess.
- Best for omri‑listed blend: Alaska Fish Fertilizer OMRI Listed 5-1-1
- Best for vitamin‑rich boost: CENTRAL GARDEN BRANDS 100099247 Fish Emul Fertilizer
- Best for wintergreen deodorized: Alaska Fish Emulsion Fertilizer 5-1-1 Concentrate 1 Gallon (Packaging may vary)
- Best for sustainable fish power: 1 Gallon Organic Fish Emulsion Fertilizer for Plants – Ideal Liquid Fish Fertilizer for Plants
- Best for deep green formula: Fertilome (10612) Fish Emulsion Fertilizer 5-1-1 (32 oz)
- Best for seaweed‑enhanced growth: Neptune’s Harvest Fish & Seaweed Fertilizer 2-3-1
- Best for kelp‑infused nutrition: GS Plant Foods Liquid Fish & Kelp Fertilizer (1 Gallon) – Organic Material Review Institute Listed Natural Plant Food for Home Gardens
- Best for odorless fish blend: Neptune’s Harvest Fish Fertilizer 2-4-1
- Best for compact odorless mix: Neptune’s Harvest Fish Fertilizer 2-4-1
- Best for gallon‑size odorless: Neptune’s Harvest Fish Fertilizer 2-4-1
Product Comparison: Best The Fish Fertilizer
Alaska Fish Fertilizer OMRI Listed 5-1-1, 115 oz
- Fish-based fertilizer for use in vegetable, fruit, and flower gardens
- Excellent for use on flowers, trees, and other plants
- OMRI listed
- For organic gardening
- Great for all indoor and outdoor plants
- NPK 5-1-1 fish emulsion fertilizer
- Fish has been used as a natural source of plant nutrients for centuries
- Easy to use, just mix with water
CENTRAL GARDEN BRANDS 100099247 Fish Emul Fertilizer, 1 Quart
- Promotes healthy plant growth with 11 vitamins
- Can be used on all indoor and outdoor plants
- 100-percent organic
- Stimulates microorganisms
- Does not burn
Alaska Fish Emulsion Fertilizer 5-1-1 Concentrate 1 Gallon (Packaging may vary)
- Will Not Burn
- Great for all plants
- Deodorized with Natural Wintergreen
- 5-1-1 fertilizer is an excellent source of organic plant nutrients
- Fish Fertilizer
1 Gallon Organic Fish Emulsion Fertilizer for Plants – Ideal Liquid Fish Fertilizer for Plants, Flowers, Fruits & Vegetables, 2-3-1 NPK – Sustainably Sourced and Hydrolyzed for Steady Growth
- ORGANIC FISH EMULSION FERTILIZER – Our liquid fish fertilizer is made from sustainably sourced fish emulsion and we use up all the parts that would otherwise go to waste. Using an environmentally conscious method, ingredients are refined fresh and 100% cold pressed to help retain all of the nutrients, vitamins, and amino acids needed to grow healthy plants.
- GROW PLANTS NATURALLY – This wonderfully organic alternative to synthetic fertilizer contains a 2-3-1 NPK ratio perfect for light and frequent applications. Promotes steady, healthy plant development throughout the growing season.
- ENRICHES SOIL – Helps build a strong foundation for your organic garden to thrive on! Use as an effective soil drench to improve fertility, structure, and encourage the growth of beneficial microorganisms like fungi in your garden’s soil.
- PRODUCE MORE – Get the most out of your fertilizer and your garden! This organic garden fertilizer helps to increase crop yields and flower blooms. Gentle enough to use as a foliar spray makes this the perfect fish fertilizer for plants, flowers, and vegetables.
- SMELL THE DIFFERENCE – This fertilizer smells like fish because it’s made from fish! Crafted with high-quality concentrated and undiluted hydrolyzed fish emulsion each bottle gives off a pungent fishy aroma. When compared, we see it like this – if it doesn’t smell, then it’s not real fish!
Fertilome (10612) Fish Emulsion Fertilizer 5-1-1 (32 oz)
- Develops deep green foliage, vigorous root systems and a solid plant structure
- Derived from fish soluble, can be used from indoor and outdoor. Can be used on plants and trees.
- Mixes with water and can be used by any convenient method of application. Shake well before use.
- 5-1-1 Fertilizer contains 5% Nitrogen, 1% Phosphate and 1% Soluble Potash.
- For plants mix 1-2 tbsp per 1 gal of water. For trees mix 4 tbsp per gal of water.
Neptune’s Harvest Fish & Seaweed Fertilizer 2-3-1, 18 Ounce
- Grow a beautiful vegetable garden
- Flowers and foliage will be stronger and more colorful
- Blooms will be more plentiful, fragrant and longer lasting
- Easy to mix and apply by hand, sprayer, or drip line
GS Plant Foods Liquid Fish & Kelp Fertilizer (1 Gallon) – Organic Material Review Institute Listed Natural Plant Food for Home Gardens, Lawns, and Vegetables
- ORGANIC MATERIALS REVIEW INSTITUTE LISTED FOR TRUSTED GARDEN CARE Certified by OMRI for use in organic growing, GS Plant Foods Liquid Fish & Kelp Fertilizer delivers reliable, natural nutrition for vegetables, lawns, flowers, and shrubs.
- SEA-AND-SOIL BASED NUTRITION Made from North Atlantic seaweed (Ascophyllum nodosum) and fresh fish hydrolysate, this liquid concentrate provides essential nutrients and trace minerals that help support healthy soil and plant development.
- IMPROVES SOIL MICROBIOLOGY & NUTRIENT UPTAKE Supports a thriving soil ecosystem that promotes strong root systems and efficient nutrient absorption — the foundation for resilient, productive plants.
- EASY-TO-USE CONCENTRATE FOR ALL PLANTS Mix 2 oz per gallon of water and apply as a foliar spray or soil drench every 2–4 weeks. Safe for use on vegetables, fruits, ornamentals, turf, and houseplants.
- MADE IN THE USA – SUSTAINABLY PRODUCED Proudly produced by GS Plant Foods as a licensed fertilizer manufacturer. No synthetic chemicals, additives, or fillers — just natural ingredients formulated for healthy home gardens and hobby farms.
Neptune’s Harvest Fish Fertilizer 2-4-1, 36 Ounce
- Neptune’s Harvest is an organic fertilizer made from fresh north Atlantic fish
- It is made by a unique cold process that protects the vitamins, amino acids, enzymes and growth hormones
- It also contains all the micro and macro nutrients naturally found in fish
- Unlike fish emulsions, Neptune’s Harvest retains the fish proteins and oils and has no unpleasant odor
Neptune’s Harvest Fish Fertilizer 2-4-1, 18 Ounce
- Neptune’s Harvest is an organic fertilizer made from fresh north Atlantic fish
- It is made by a unique cold process that protects the vitamins, amino acids, enzymes and growth hormones
- It also contains all the micro and macro nutrients naturally found in fish
- Unlike fish emulsions, Neptune’s Harvest retains the fish proteins and oils and has no unpleasant odor
Neptune’s Harvest Fish Fertilizer 2-4-1, Gallon
- An organic fertilizer made from fresh North Atlantic fish
- Made by a unique cold process that protects the vitamins, amino acids, enzymes and growth hormones
- Contains all the micro and macro nutrients naturally found in fish
- The nitrogen and other nutrients are chelated, so they are readily available for plants consumption
- The fish proteins and oils are retained and the fertilizer has no unpleasant odor
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon.com at the time of purchase will apply to the purchase of this product.
Buying Guide
FAQs
What key factors should I look at when comparing fish fertilizers?
Focus on the NPK ratio, the concentration (liquid vs concentrate), OMRI certification, and any added ingredients like kelp or seaweed. Also consider the size of the container, odor level, and whether the formula is safe for indoor use. These elements affect nutrient availability, application frequency, and overall garden compatibility.
How does the NPK ratio influence which plants I should use a fertilizer on?
A higher nitrogen ratio (e.g., 5‑1‑1) promotes leafy growth, making it ideal for vegetables, lawns, and foliage plants. Ratios like 2‑3‑1 or 2‑4‑1 have more phosphorus and potassium, which support root development, flowering, and fruiting, so they work well for blooming flowers and fruit‑bearing crops. Choose the ratio that matches the growth stage you want to encourage.
Which product gives the best value for money?
Generally, the larger containers such as the 1‑gallon Alaska Fish Emulsion (5‑1‑1) or the 1‑gallon GS Plant Foods Liquid Fish & Kelp Fertilizer provide the lowest cost per ounce. While the 18‑ounce Neptune’s Harvest and the 115‑ounce Alaska OMRI‑listed formulas are slightly pricier per ounce, they still offer good value because they are highly concentrated and require less frequent application.
Do fish fertilizers have a strong smell, and how can I minimize it?
Most fish emulsions emit a noticeable fishy odor, especially the 1‑gallon organic fish emulsion that advertises a pungent scent as a sign of authenticity. Products that are deodorized, such as the Alaska Fish Emulsion with natural wintergreen, or those that retain proteins but claim “no unpleasant odor” like Neptune’s Harvest, are better for indoor or close‑quarter use. Diluting the fertilizer according to label directions and applying it in the early morning can also reduce odor perception.
What are the practical differences between liquid, concentrate, and emulsion formulas?
Liquid fertilizers are ready‑to‑use and can be applied directly as a soil drench or foliar spray, making them convenient for frequent, light feedings. Concentrates require dilution, which lets you adjust strength for different plant types and reduces shipping weight. Emulsions blend the benefits of both, offering a stable mixture that delivers nutrients slowly while still being easy to mix with water.
Why is OMRI certification important for organic gardeners?
OMRI (Organic Materials Review Institute) listing confirms that the product meets strict organic standards and can be used in certified organic production. This certification reassures gardeners that the fertilizer contains no prohibited synthetic chemicals and that it supports soil health. Choosing an OMRI‑listed product, like Alaska Fish Fertilizer or GS Plant Foods, helps maintain organic integrity in your garden.
Can I use the same fish fertilizer for both indoor and outdoor plants?
Yes, many of the listed products, such as Central Garden Brands Fish Emulsion and Fertilome 5‑1‑1, are formulated for both indoor and outdoor use. However, for indoor environments you may prefer low‑odor options or those that are specifically deodorized to avoid strong smells. Outdoor applications can tolerate stronger‑scented formulas, which often contain higher protein content for robust growth.
How do added ingredients like kelp or seaweed improve the performance of fish fertilizers?
Kelp and seaweed introduce trace minerals, natural hormones, and vitamins that enhance root development and stress tolerance. Products such as GS Plant Foods Liquid Fish & Kelp Fertilizer combine fish nutrients with seaweed to boost soil microbiology and improve nutrient uptake. This synergy can lead to stronger, more resilient plants and higher yields compared to fish fertilizer alone.