I've used fish emulsion for years on my Bonsai but must say I haven't tried on my orchids. And I really don't know why as it is good for other growing plants. Mine is also in a plastic bottle so at least if I drop it won't break. I think after this discussion I will try on orchids. I am sure no immediate results will be known.
Feed weekly weakly no matter the strength or use of any fertilizer. but I would recommend looking at the inert and active ingredients. Fish emulsion has a high & low table of the periodic table. Including strong traces of minor and major trace elements. Just make sure you use fish emulsion