Yes, all school subjects will always be capitalized in German.
Also all fruits will always be capitalized in German.
And all feelings. And all things that are made of steel or wood. And all liquids. And ...
To make it short:
In German all nouns are always capitalized.
This makes it easy to identify nouns in a German sentence or phrase:
- Der Gefangene floh. - The prisoner fled.
- Der gefangene Floh. - The caught flea.
All other parts of speech are not capitalized as long as they are not the first word in a sentence. So, it can be unclear only for the first word of a sentence if it is a noun or not. From all other words in a sentence you can read it from it's first letter.
This is also true for titles and headings! In English you are used to capitalize important words in headings (In the following example, only »in« seems to be not so important):
Those Magnificent Men in Their Flying Machines
But »Magnificent«, »Their« and »Flying« are no nouns, so in the German translation you can't write them capitalized, even if they appear in a title or heading:
Die tollkühnen Männer in ihren fliegenden Kisten
(»Those«/»Die« stands at the beginning of the title, and this is why they are capitalized in both languages. This rule is identical in German and English.)
On the other hand side: In english you are used to capitalize adjectives that are derivated from proper nouns like in this example:
"Finger" is a German and an English word.
But »German« and »English« are no nouns, but adjectives, so you have to write them in lower case in a German translation. But »word« is a noun and therefore its German translation has to be capitalized:
"Finger" ist ein deutsches und ein englisches Wort.