Absolutely! Any form or natural or synthetic soil fertilizer/soil amendment can be abused!

Use moderately.

My particular beef is that Fish emulsion is a HIGH N to PK ratio that is 5 N to 1 P and K I like my ferts closer to equal like 5-5-5, 4-6-6, 3-2-2

Just one old mans 2¢

"Can using fish emulsion as fertilizer produce any unwanted results? "

yep, I stinky fishy smell :)

I like to use it for leafy greens and herbs, like basil, parsley, lettuce etc, it's a great fertiliser for things like that, particularly if it's something that you dont want to flower. also a great one to use if plant is suffering nitrogen difficiency, it will green them up very quickly.

trance

Different formulas have different N-P-K specs. I found a herring-based emulsion at 4-1-1, and other types at 2-3-2. Just do some research and make sure you're getting what you need.

Some fish liquids really stink, but I've found that the odour doesn't last long. I use fish stuff indoors on the starts and houseplants-- works great. I usually add some kelp/seaweed with it.

If you don't dilute it weak enough it can burn up young starts

I use a fish hydrolysate product (Neptune's, but I've seen other brands). I love it as a houseplant & general fertilizer. This alone has none of the awful smell of regular emulsion and is supposedly better in micro/macro nutrients. I love seaweed as another source of great nutrients, but it has a little smell if I use it in the houseplants (although my wife's KEEN, Lassie-like smell does not complain about it, so it can't be that bad).