The best topic to discuss in a persuasive essay is that of fish farms. "Environmental issues" is a very large, broad topic that would be difficult to discuss in a short essay. "Land destruction" and "water pollution" are negative phenomena, and very few people want to consider both sides of the argument, as the consequences are objectively negative. However, few people know about fish farms, which means that they are open to be persuaded. Moreover, this is a narrower topic, which makes it more suitable for a persuasive essay.
