This is an interesting idea. If neither biologies used the same fuel molecules then they wouldn’t compete for resources, but perhaps they would compete for space? But then if both biologies were that different from each other would they be able to even live in the same environment?
The sci-fi book Children of Ruin (sequel to Children of Time) covers this somewhat. There humans encounter a planet with a breathable atmosphere but with a toxic environment that slowly kills them.
On the other hand, the two biologies could be so different from each other that they don’t interact at all.
This is an interesting idea. If neither biologies used the same fuel molecules then they wouldn’t compete for resources, but perhaps they would compete for space? But then if both biologies were that different from each other would they be able to even live in the same environment?
The sci-fi book Children of Ruin (sequel to Children of Time) covers this somewhat. There humans encounter a planet with a breathable atmosphere but with a toxic environment that slowly kills them.