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Eli’s Fish Facts: Mummichog!

Eli’s Fish Facts: Diamondback Terrapin

Fundulus heteroclitus

Mummichogs are a common fish found in our estuary, and are also commonly mistaken for their fish “twins”, the striped and banded killifish. While it can be difficult to tell these species apart (especially since they have been known to interbreed at times, further confusing scientists), one indicator is that the snout of the mummichog is wider than that of the killifish. Another indicator we’ve noticed lately at CURB is that breeding male mummichogs often develop a black spot towards the rear of their dorsal (back) fin, and vertical bands along their sides. Mummichogs breed for several months a year, so it can be quite noticeable.

Mummichogs are one of the most common fish we’ve caught at CURB in recent years, and are also a very important species in the food web for the whole Hudson River estuary. They are omnivorous and eat lots of little plankton and smaller fish, while they also make up meals for many of the larger migratory species in the water. This little-known fish has an outsize role of importance here in our estuary.