Mummichog become established on the Atlantic coast of Portugal and southwestern Spain, starting in the 1970s and some have now reached the western Mediterranean basin. There may also be introduced populations in Hawaii and the Philippines. As bait fish, mummichogs are sometimes released in freshwater habitats, where they can survive, and there have been reports of individuals in New Hampshire ponds, as well as the upper Ohio River and Beaver River. The mummichog is a common fish in coastal habitats such as salt marshes, muddy creeks, tidal channels, brackish estuaries, eelgrass or cordgrass beds, and sheltered shorelines. It can be found
Creature Catalogue recommend it. Brinsley felt that organizing the book in sections by type of creature rather than just alphabetically like "AD&D"<nowiki>'</nowiki>s "Monster Manual"s "should certainly make life easier for those DMs who design their own adventures, and know what sort of monster they want, rather than by name". He also felt that the comprehensive references to all the monsters appearing in the "D&D" boxed sets would solve the problem of having to remember in which set a particular monster appears. He concluded the review by stating, "basically, this book contains all you could ever wish to know about monsters in the