What kind of fertilizer do we need for an orchid, please? For several years we used to give it an ice cube...

There's no nutritional value in an ice cube.

If you only have one orchid, use whatever fertilize you use on your houseplants. They aren't fussy.

Do not water your orchids with ice cubes. That is nothing more then a sales gimmick!
For the most part, the orchids we grow are tropical plants. Tropical as in warm climates. As far as I know, it never rains ice cubes in tropical climates.

Fertilizer to be used can be just about anything for indoor plants. I use an 20-20-20 blend at 1/2 tsp. per gallon.