eSHa alx is specially developed for ornamental fish against parasitic species of Crustacea (Maxillopoda) such as Argulus (carp lice) Lernaea (anchor worm) Ergasilus (gill lice) Salmincola (gill lice) etc. The parasitic Crustacea occur on and in the skin of fish and on the gills. The symptoms caused by these parasites are similar: trying to jump out of the aquarium/pond; scraping the entire body along stones and the bottom; visible areas where parasites have bitten (which subsequently become white as the skin dies); pale gills; listless behaviour; skittishness; weight loss; separating from the group; not eating; etc. Remove shrimp and crayfish! eSHa-alx is well tolerated by ornamental fish in freshwater aquaria and ponds and in marine aquaria. 20 ml is for 4000 Litres.