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 type (Dungeons & Dragons) animals despite their real-world bases being more closely related to vermin type creatures. Creatures deemed inconsequential by DMs or designers are not given any creature type at all, instead being treated as "set dressing" unless a specific game effect targets such non-creatures. Examples include actual-sized spiders, sparrows, fleas, worms, shellfish, and mice. "Swarm" type creatures are occasionally written to represent such otherwise nonthreatening creatures if they were to group together by some force of magic within the game world. Under the rules of D&D, animal type creatures do not have an Intelligence score higher than 2. When a designer makes