I have mixed fish emulsion at 1 tsp per gallon; I think you can safely add more, perhaps a tablespoon per gallon. I used to alternate it with other fertilizers & only gave it every few months. I'm sure more often is fine. . . after all there is probably no fertilizer as good as fish.

The problem I have is the smell. Even though it is "deodorized" my cats are way too curious & I can detect the odor also. Outside use was a disaster as raccoons dug up so many plants to find that fish!

I understand there is now some mint smelling fish emulsion available. I'm thinking of trying it.

Terri

My mother used fish emulsion and I use fish emulsion on all potted plants.
I use it as a tonic, a supplement to regular fertilizer.
I shake the bottle and then add 1 or 2 capfuls per 1/2 gallon of water.
I used a heavier concentration on some domed AV's and I had mold growing on the soil of a few plants. I don't know if that was the heavy concentration of fish emulsion or not. It was coincidental, certainly.
I tend to use it abt every other watering on the AV's and every watering on the large foliage plants.
It is more a ritual rather than any evidence it makes one whit of difference, although mom swears by it.
I do believe it adds micronutrients and with the peat based mixes, the plants are almost hydroponic in terms of food.