some low-light plants are really plants that can do well in low light, but can also manage in higher light, others will only do well in low light, called shade plants in this graph.
What this shows is that photosynthesis increases with light intensity to a point, called the compensation point, at which an increase in light does not result in an increase in photosynthesis. This point is reached at much lower light levels in shade plants. If we were to follow the blue line out further to the right (higher light intensity) we would reach a point at which photosynthesis would start to decrease. This is called 'photoinhibition', where high light levels causes a decrease in photosythesis. Putting low light plants in a high light tank may very well be a situation where the plants are exposed to a level of light that will induce photoinhibition, and the plants won't do well, or at least as well as they would in lower light. Of course this can be dealt with by creating shade with other plants or wood.