Temperature plays an important role in sex reversal of some species of fishes when required. I want to know what other factor can play the role in sex reversal in fish?
Fishes are neither hermaphrodites nor have social hierarchy where social parameters can affect. It may be a conditional factor which provokes them to sex change. But the question is what?
Sex change is the same thing as sequential hermaphroditism and there are plenty of species of fish which are sequential hermaphrodites. Many fishes do have social hierarchies. I have given you the correct answer to the question. There is even a wikipedia page on sequential hermaphroditism which covers fish as well https://en.wikipedia.org/wiki/Sequential_hermaphroditism
Are you asking for a specific species and are you really asking for sex change (=hermaphroditism) and not sex determination? Or are you asking for fish which do not regularly change sex?
Here is an article on sex change in fish. I can give you more if you like. https://link.springer.com/article/10.1007%2FBF00005025?LI=true
Here is an article about sex determination in fish http://www.sciencedirect.com/science/article/pii/S0044848602000571
If this is sex reversal during the sex determination phase I would say temperature and increased stress may be a factor. If these fish are in a water body and not in tanks I would be concerned about any possible chemicals in the water (estrogenic chemicals are frequently examined for this). Photoperiod may also be a factor: http://www.sciencedirect.com/science/article/pii/S002209811400197X