Sea Urchins, Echinometra Sp. Betta Harptail Blennies are passive fish

Harptail Blennies are passive fish rarely bothering other tankmates

live algae cells per ml

Alternatively

it will tolerate others of its own species

Then use a maintenance dose of 5 mL for each 80 L (20 US gallons) with additions of livestock or the disruption of the biofilter through cleaning or medications

Sea Urchins, Echinometra Sp. Betta Harptail Blennies are passive fishThe Pencil Urchin of the Eucidaris genera is also known as the Mine or Club Urchin. It has a brown, sometimes mottled body with stubby, thick spines radiating out in all directions. The spines are surrounded by basal plates. Never try to pry it out of a hole, as you will break its spines before it lets go. As it ages, its spines may become covered with coralline and other types of algae. During the day it will seek shelter in the rocks; at night it