Liquid fish fertilizers come in different forms and qualities. Most are fish emulsion fertilizer products, which means that the important oils, amino acids, vitamins, hormones, and enzymes have been been either separated for use in different products or killed in the high temperature manufacturing process. The result is generally a lower quality product with a lower nutrient content than a hydrolysate.
A fish hydrolysate fertilizer (which is what this product is - it's not a fish emulsion) means that fish are enzymatically cold pressed, keeping the oils, amino acids, vitamins, hormones, and enzymes in the product. The result is a nutrient-rich product that has many trace minerals and other benefits.
Organic fish fertilizer is often applied with effective microorganisms, mycorrhizal fungi, compost tea other liquid organic fertilizers. Many people swear by this as a foliar feed! If mixed with EM and water (and perhaps humic acids) and left to sit for a few hours before application (but not too long), the slight odour will be drastically reduced.
I have done a fair bit of research on the "sustainability" of this product and from what I can gather, it is okay. While it is my belief that we should be careful not to overfish our seas as many species are threatened or already extinct, the Pacific Dog Shark is apparently fished sustainably here in BC below the total allowable catch.
The fishery that supplies fertilizer fish for this product is in the process of undergoing third party assessment by the Marine Stewardship Council, at a cost of more than $100,000. Also, the product uses fresh fish that are a byproduct of goods made for human consumption, therefore diverting them from the landfill.
The fish hydrolysate is mixed with water in a watering can, sprayer, or irrigation system. It is best applied early in the morning, while evening would be the second choice. Preferably, liquid fish fertilizer is applied in smaller, regular does, monthly or even weekly.
Keep the container closed tightly and do not store the product in diluted form, as it will go rancid. Here are some application rates:
Here is some more information on application rates. If you have time, you may want to go through them all, as the home and garden one alone is not really useful for every situation.