Grandmapele,
There are many different traditions of torma. Generally speaking, red tormas are typically used for Yidams, Protectors, and the retinues of both, while white are used as food offering torma in place of food items in peaceful outer offerings, as well as for local guardians and other places in certain rituals. As we can see from various sources: white, yellow, red, and black are used for the four actions being pacifying, increasing, controlling, and wrathful respectively. There is a special Ratna Shugden torma that is yellow. I've seen the tormas to Dorje Shugden 5 lineages being colored according to this. We can understand that if we were doing Protector practice with special emphasis on pacifying, that all the tormas could be white and so forth. Black tormas would be used for rituals emphasizing wrathful energy, so no, this is not exclusively for fire puja to wrathful deities.
That being said, if we make the typical tormas red and white, these are the basis of the offering. There is no reason why we can't visualize specific colored tormas being offered. Though we have traditional rituals and explanations, it has been both shown and explained by the Gurus throughout Buddhist history that these explanations are generally a skeleton and that spontaneity and a vivid imagination are important. Also, until we have strong experience of the three principal aspects and at least the generation stage, we should be quite careful about getting over-excited to offer wrathful black tormas, as if we're only doing it because it's raw and exotic. We shouldn't mistake our ill-motivated attraction to violence for being wrathful energy used with pure motivation. A clear distinction must be made. The combination of compassion and wisdom in action equals 'skillful means'. These must be the foundation of the four types of actions, especially wrathful.
