Comparison: Best Fish It Fertilizer (Updated | Dec 1st)
If you’re looking to give your garden a natural boost, you’ve probably heard about fish-based fertilizers—but with so many options out there, which one’s truly the best? We’ve dug into the details, tested popular picks, and compared ingredients, effectiveness, and value to help you decide. Whether you’re growing veggies, flowers, or lush greens, the right fish fertilizer can make all the difference.
- Best for omri certified blend: Alaska Fish Fertilizer OMRI Listed 5-1-1
- Best for vitamin-rich emulsion: CENTRAL GARDEN BRANDS 100099247 Fish Emul Fertilizer
- Best for odor-free formula: Neptune’s Harvest Fish Fertilizer 2-4-1
- Best for wintergreen deodorized: Alaska Fish Emulsion Fertilizer 5-1-1 Concentrate 1 Gallon (Packaging may vary)
- Best for compact odorless pack: Neptune’s Harvest Fish Fertilizer 2-4-1
- Best for pungent fish power: 1 Gallon Organic Fish Emulsion Fertilizer for Plants – Ideal Liquid Fish Fertilizer for Plants
- Best for aquarium plant boost: API LEAF ZONE Freshwater Aquarium Plant Fertilizer 8-Ounce Bottle
- Best for deep green growth: Fertilome (10612) Fish Emulsion Fertilizer 5-1-1 (32 oz)
- Best for fish-kelp fusion: GS Plant Foods Liquid Fish & Kelp Fertilizer (1 Gallon) – Organic Material Review Institute Listed Natural Plant Food for Home Gardens
- Best for seaweed enriched: Neptune’s Harvest Fish & Seaweed Fertilizer 2-3-1
Product Comparison: Best Fish It 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
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
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
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
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!
API LEAF ZONE Freshwater Aquarium Plant Fertilizer 8-Ounce Bottle
- Product Type: ARTIFICIAL PLANT
- Package length: 19.558 cm
- Package width: 3.048 cm
- Package height: 4.572 cm
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.
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 & 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
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 N‑PK ratio should I choose for my garden’s needs?
For general vegetable and flower production, a balanced 2‑4‑1 or 2‑3‑1 ratio like Neptune’s Harvest provides more phosphorus for strong root and bloom development. If you need rapid leafy growth, a higher nitrogen ratio such as 5‑1‑1 found in Alaska’s fish emulsion is ideal. Consider the plant stage: use higher nitrogen early, then switch to phosphorus‑rich formulas for flowering.
How important is an OMRI listing when buying fish fertilizer?
An OMRI (Organic Materials Review Institute) listing guarantees the product meets organic certification standards, which is crucial for certified organic gardens. Both Alaska Fish Fertilizer and GS Plant Foods Liquid Fish & Kelp carry OMRI certification, ensuring they’re safe for organic production. Products without this listing may still be natural but lack official organic verification.
Do fish fertilizers have a strong odor, and does it affect usability?
Traditional fish emulsions can be pungent, but many modern formulas are deodorized or have a milder scent. Alaska’s 5‑1‑1 concentrate is deodorized with natural wintergreen, while Neptune’s Harvest retains fish proteins but advertises a low‑odor profile. If odor is a concern for indoor use, choose a deodorized or low‑odor product.
Which product offers the best value per ounce?
When comparing price‑per‑ounce, larger containers like the 1‑gallon Alaska Fish Emulsion or the 1‑gallon GS Plant Foods Liquid Fish & Kelp typically provide the lowest cost per ounce. Smaller bottles such as the 18‑ounce Neptune’s Harvest are convenient for trial use but cost more per ounce. Calculate total cost divided by volume to determine the most economical option for your budget.
Can I use fish fertilizer on both indoor and outdoor plants?
Yes, most fish emulsions are formulated for universal use. Products like Central Garden Brands Fish Emul Fertilizer and Fertilome’s 5‑1‑1 are labeled safe for indoor houseplants as well as outdoor gardens. Just follow dilution instructions to avoid over‑feeding, especially in confined indoor spaces.
How do I apply fish fertilizer correctly for maximum benefit?
Mix the recommended amount of concentrate with water—typically 1‑2 tablespoons per gallon for foliage and up to 4 tablespoons per gallon for trees. Apply as a soil drench or foliar spray every 2‑4 weeks during the growing season. Consistent, light applications encourage steady nutrient uptake without risking burn.
What extra benefits do fish‑and‑seaweed blends provide over pure fish emulsion?
Seaweed adds trace minerals, hormones, and natural growth stimulants that complement the nitrogen and phosphorus from fish. Products like GS Plant Foods Liquid Fish & Kelp and Neptune’s Harvest Fish & Seaweed blend improve soil microbiology and boost nutrient absorption. This combination often results in more vigorous root systems and richer, longer‑lasting blooms.