Synthetic chemicals Levamisole, FK-565 (Lactoyltetrapeptide from Streptomyces olvaceogriseus), Quaternary ammonium compounds (QAC).
Biological substances  
1) Bacterial derivatives MDP (Muramyl dipeptide from Mycobacterium species), Lipopolysaccharide (LPS), Freund’s complete adjuvant (FCA), EF203 (fermented egg product), Peptidoglucan (from Brevibacteriumlactofermentumand Vibrio sp.), Clostridium butyricum cells, Achromobacterstenohaliscells, Vibrio anguillarumcells (Vibrio vaccine)
2) Yeast derivatives b-1, 3 glucan, b-1, 6 glucan
3) Nutritional factors Vitamin C and E, n-3 fatty acid
4) Hormones Growth hormone, Prolactin, tri-iodothyronine
4) Cytokines Interferon, Interleukin
5) Polysaccharides Chitosan, Chitin, Lentinan, Schizophyllan, Oligosaccharide
6) Animal and plant extracts Ete (tunicate), Hde (Abalone), Glycyrrhizin, Firefly squid, Quillaja, Saponin (Soap tree)
7) Others Lactoferrin, Soyabean protein, Quil A, Spirulina, Achyranthesaspera (Herb), Mucorcircinelloides (Fungi)
Table 1: Immunostimulants evaluated in fish and shrimp.