Many of us grew up catching little fish called “minnows”. But what are minnows? Baby trout or maybe some other young freshwater fish? Or maybe even salmon spawn? Not quite. Minnows are actually a small freshwater fish that belongs to the carp family. They belong in their own sub family named Leucisnae. Many genus branch off from this sub family. ( For those not taxonomically inclined this simply means that under this family of fish many different kinds of it branch off to create their own “genus” as it is called in biological terms).
One of these genus’ you are most likely familiar with from your childhood would be Pimephales which is also called the bluntnose minnow. A picture of this type of minnow is shown. These type of minnows then branch into four species. These being Pimephales notatus (the most common species and what is truly considered to be the bluntnose minnow), Pimephales promelas (also known as the fat head minnow), Pimephales tenellus (a.k.a Slim minnow), and Pimephales vigilax ( a.k.a bullhead minnow).
By this time and this far into reading you are most likely asking yourself ” Hey, self, when I grew up I remember stickle-backs and the author hasn’t even mentioned them? So what are they? Are they a type of minnow too? Well reader, no not really. Stickle-backs actually belong to a completely different family called Gasterosteidae. A neat thing about stickle-backs besides of their spikes that stick out of them is the fact that they don’t have any scales although some species of them have armor plates protecting them. Something else that is interesting about them is the fact that all species of them have the same mating behaviors which is very uncommon in fish. The stickle-back that most people have caught as kids would be Gasterosteus aculeatus sub species aculeatus also commonly known as the three-spined stickle-back. As the name explains it has three spikes or “spines” sticking out of its back. You may remember those because when you were younger and holding one of these kinds of fish it stuck right into your hand. Just as the bluntnose minnow, stickle-backs are very small full grown fish and the reason they are small is not because they are juveniles.
So to recap: The most common minnow that you most likely caught as a child was a bluntnose minnow or scientifically known as Pimephales notatus. These are small fish that grow to be 11 millimeters or less and are closely related to carp. They are not juveniles of another species but are there own species (although you may have caught a newly born fish of another species and thought it to be a minnow at some point). The other most common “minnow”, the stickle-back is actually not a minnow at all and belongs to a completely different family. There scientific name is Gasterosteus aculeatus sub species aculeatus. These fish are more closely related to sea horses and are found as often in the ocean as they are in freshwater lakes or ponds. (Although some minnows do live in saltwater stickle-backs are more notorious for it ). Hopefully this article answered the question ” What is a minnow?” or “What minnows actually are”.
