Organic fertilizers are fine for orchids as long as their nitrogen content is 20% or less. Seaweed type fertilisers do not generally meet this requirement, and so are not recommended.
Fish emulsion fertilizers are widely used in Greenhouse orchid growing, but because of their strong smell, are not a good choice for home use.
There are plenty of nutritious and acceptable foods for orchids. The fertilizer does not need to be specially formulated for the orchid plant.....which sustains itself primarily on moisture and air. Although adequate nitrogen is necessary for blooming, too much nitrogen can cause problems.
Organic and seaweed fertilisers are a good idea when you are growing food, however they are not really needed in orchid culture. This presumes, that you are not going to eat your orchid!