Background: Aquatic animals require different minerals and elements for their normal life processes. Elements are broadly classified into two groups including macro-elements and micro-elements. Trace elements are part of micro-elements and are divided into the essential trace elements and non-essential trace elements. The essential trace elements are necessary for life , but are toxic in high dose, whereas non-essential trace elements can cause toxicity even in low dose . Essential trace elements are components of the skeletal structure, maintenance of the colloidal systems (osmotic pressure, viscosity, diffusion) and regulation of acid–base equilibrium as well as important components of hormones, enzymes, enzyme activators and are involved in a wide range of cellular (e.g. oxygen transport, respiration, enzyme activity) and physiological (e.g. growth, reproduction, vision, immunity) processes of fish.

Materials and Methods: Databases of ScienceDirect and Fish Diseases and Disorders were searched.

Results: Unlike most terrestrial animals, aquatic organisms absorbed inorganic elements which the elements may increase as a result of environmental contamination by human or in order to water treatment with drug. An excessive intake of minerals through either the diet or gill uptake can cause toxicity and in addition to fish can cause problems for human and animals that feed from these fish.

Conclusion : Therefore, a fine balance between the mineral deficiency and surplus is vital for aquatic organisms to maintain their homeostasis through either increased absorption or increased excretion.