Elacatinus horsti

Elacatinus horsti, commonly known as the Yellowline goby, is a small reef-dwelling goby. The Genus Elacatinus are all small fancy coloured gobies which also have a symbiotic relationship with large fish because they act as cleaner fish. This helps the large fish getting rid of the ectoparasites and get the goby's belly filled with their main food source, parasites. E. horsti are very dark, almost black on top which shades into white on the belly. They also have a thin horizontal bright yellow stripe running from the eyes all the way to the caudal fin.

They always live close to tube sponges or other large sponges and can be very shy, especially when just introduced in the aquarium. These fish can't really clean an ich outbreak, but are able to help keeping fish parasite-free to prevent outbreaks and thus should never used as a solution and only as preventive measure. Sometimes the constant cleaning can stress a fish, but usually this causes no problems and only helps the fish. Keeping evelynae well fed will probably help to prevent it from contantly cleaning in the first place. They also don't need large fish and can live in a nano tank as well, but you do need to make sure it can eat multiple times a day or even better only place them in a tank with enough zooplankton.