Fishes of Missouri. Tips for Using the Key to Families of Missouri Fishes (Page 23). Couplet #1. Couplet #1 needs no explanation. Be sure to look at the drawings after reading the text. There should be no confusion. Couplet #2.
Tips for Using the Key to Families of Missouri Fishes (Page 23)
Couplet #1 needs no explanation. Be sure to look at the drawings after reading the text. There should be no confusion.
This one is easy; just look at the location of the mouth in reference to the eye. You are simply ruling out paddlefishes and sturgeons here.
Self-explanatory and should be easy!
Couplet #4 is to rule out gars. This one is easy; just look at the fish’s snout.
Couplet #5 is extremely important and can be a little confusing. You are looking for the adipose fin. This fin is just a fleshy piece of tissue toward the tail of the fish, behind the regular fins. Do not confuse the soft dorsal fin of a bass or walleye or other fish with the adipose fin.
Don’t let the term (Bullhead) confuse you here. The bullhead catfish family refers to all catfishes including channel, flathead, blue and the madtoms as well. This one should be easy. Is it a catfish or not?
This one stumps people all the time. Keep it simple. Does the mouth extend well beyond the front of the eye or not?
Down to the last few families with an adipose fin—Trouts and Smelts. If you get to this couplet, which should be unlikely, just look at the illustrations. Trouts don’t look anything like smelts!
A simple question. Does the fish have pelvic fins or not? Here’s a tip: If you are a little confused, note that the only choices for 9a are shown in couplet 10. Do you really have an eel or a cavefish?
If you make it to this couplet you have an eel or a cavefish and they don’t look anything alike so you shouldn’t have a problem.
Most of the time you end up going through this one on the way to further couplets so it is important that you get it right. Look for the normal anus position to verify it is not a Pirate Perch and keep in mind that the Pirate Perch is not very common and you are not likely to see one. If you can’t find the anus in the normal position near the anal fin, maybe you have a pirate perch. Look at the illustration to verify at that point.
Does it have a single or divided dorsal fin. Look at the illustrations. The divided dorsal might have a small connection in the middle but you can still see it is not a single fin.
Here you are looking for the extremely long dorsal fin to eliminate bowfins. Its dorsal fin is more than half the length of its body and don’t forget to look at the illustration as the bowfin is very distinctive.
This one is easy. Is the tail fin forked or rounded?
Self-explanatory. Look at the illustrations for the duckbill shaped snout on pikes.
Watch for the axillary process (shown in illustration) as it only appears on Herrings and Mooneyes (Couplet 17). Also, look closely at the illustrations of the gill opening beneath the fish. It works!
Self explanatory. Look for the position of the dorsal fin.
This is a very important couplet that distinguishes between minnows and suckers. You have to determine if the anal fin is very far back or not. Follow the instructions. Note: The carp, which is in the minnow family, can fall out as a sucker here so you have to further eliminate the carp possibility in couplet #19. Remember, the carp also has fleshy barbels at the corners of its mouth.
Be careful with this couplet. It is simply to determine if you have a carp (minnow family) or if you continue on with suckers.
On this one I would concentrate on the position of the dorsal fin to determine my next couplet.
Is the dorsal fin mostly over the anal fin base or somewhat behind it? Look at the illustrations for help. Killifishes are more long and slender than Livebearers (mosquitofish).
Self-explanatory. Look at the illustrations. The Cod is long and snake-like almost. Watch for the single barbel on the chin if you are confused. It would be rare to see a Cod, by the way.
This is one where it helps to just look at the illustration as 23a (Silverside) is a slender fish with at tiny spinous dorsal that is sometimes hard to find without a probe. The fish is needle-like just like in the illustration.
This one separates Silversides from Mullets. Remember what I said in Couplet #23, the Silversides are very slender and stick-like, even when compared to a mullet.
Remember, Sculpins don’t have scales and they don’t look like other fish (see illustration) except for Darters which are found in the Perch family. This one shouldn’t be a problem.
Count correctly here and you’ll be okay!
Look at the connection between the spinous and soft dorsal as indicated in the illustrations.
Does the tail fin have a notch or not?
This one is easy. If the soft dorsal is much longer than the spinous dorsal it must be a Drum. Look at the illustrations; Drum are totally different looking than Perches.