An example of neutralism is interaction between a rainbow trout and dandelion in a mountain valley or cacti and tarantulas living in the desert. Neutralism occurs when two populations interact without having an effect on the evolutionary fitness of each other.
Neutralism is a type of interspecific interaction, which is the interaction between species. These interactions may have effects on the species' populations. In neutralism, interactions are incidental or indirect and are said to not have an effect on either population. Other types of interspecific interactions include competition, amensalism, mutualism, the interactions between predators and prey, and the relationships between pathogens, parasites and their hosts.