Couldn't hurt. If the fish emulsion was what I had on hand I would not hesitate to use it.

no leaves, no water! Wait till leaves are 3-4" before its first feeding.........

Fish emulsion could be a great one to add if you have a lot extra, apply conservatively until the tree is really in growing mode. I have had problems with raccoons and coyotes digging up my plants when I use fish-based products so I can’t with mine, consider your locals if you are prone to same critters

A long-time favorite from some seasoned growers that I have asked all say to use Epsom salts at about a cup per inch diameter of trunk base, watered in. This can really give plants a jump start. Check your local drug store or the like for a great deal on your wake up fertilizer. Or you could use sul-Po-mag at the same rate (sulfur.potassium.magnesium) which is also sold as langbeinite, a natural mineral

-s