The mummichog, Fundulus heteroclitus, was first used in the laboratory as a source of ripe eggs and sperm to provide developing bony-fish eggs. These in turn were used mostly to study embryological processes and responses to various chemicals. Other investigations at the end of the nineteenth and beginning of the twentieth centuries dealt with regeneration, developmental genetics and hybridization, osmoregulation, behavior, and pigmentation, especially color change. Except for experiments on chromatophore control, endocrinological studies did not get underway until the 1930s. They have included the functioning of the thyroid, adrenal, and pineal glands, and the endocrine control of reproduction, growth, osmoregulation, and calcium metabolism. Among more recently studied subjects are survival at subzero temperatures, adaptation to stress, weightless orientation in space, circadian rhythms, and the bioassay of the exophthalmos-producing substance of man as well as other physiologically active factors. The single attribute of the mummichog that has been most responsible for its remarkable popularity as a laboratory animal is its hardiness in captivity. Despite the fact that it is not widely available like the goldfish, is not easily bred in aquaria like the livebearing guppy, and has no value as a food or game fish like the trout, the mummichog has made a most substantial contribution to experimental biology

Author notes

1From the Symposium on Mechanistic Approaches to the Study of Natural Communities presented at the Annual Meeting of the American Society of Zoologists, 27–30 December 1983, at Philadelphia, Pennsylvania.