The Tadpole Madtom, Noturus gyrinus

Robin Engelking

oturus is a genus in the family Ictaluridae. Ictalurids are found in North and Central America east of the Rockies from Canada to Guatemala. Noturus is the largest group in this family and they are found in many states, including Minnesota.


Noturus gyrinus


The tadpole madtom is usually found in streams and riffles, but can occasionally be found at the margins of lakes. They are often found among stones in rocky streams. They can also be found under branches, leaf detritus or even in old cans. The best way to collect madtoms is with a seining net or a kick net and if you're really lucky you might find them in an old can or bottle. If you net something that reminds you of a small bullhead, you might have a tadpole madtom. They have smooth, scaleless skin that is yellow brown to brown on the dorsal surface with a cream or white belly. There are four pairs of prominent barbels framing a wide thick-lipped mouth. The head is broad and flat with very small eyes and in a healthy fish the barbels are held pointed forward forming a "cup". You can usually locate your fish's lair by looking for the tips of the barbels sticking out. This is how the fish keeps track of what is going on in its tank. I have had my female tadpole madtom for three years now and when I got her she was a little over an inch long, now she is approximately 5? inches long. 

The adipose fin starts far forward on the fish's back and is matched by a long anal fin on the belly. Both of these fins are separated from the caudal fin by a small notch. The dorsal and pectoral fins have thick, sharp spines and you need to be aware that these spines are venomous and can give a nasty sting. I have never been stung by my fish, but people who have, say it is very painful.

Madtoms are shy and seldom appear during the day. They prefer to prowl the tank at night and will glide gracefully around it searching for food. Madtoms are omnivores and thus easy to feed. They will eat almost anything that will fit in their mouths. I feed mine Hikari sinking carnivore pellets, brine shrimp pellets, chopped earthworms and glass shrimp but they will also eat feeder guppies and the occasional tank mate. They can swallow surprisingly large fish. Mine managed to eat a couple of 3 inch shiners. I usually feed my fish in the evening just after I turn out the tank light.

Because they are native fish and used to cool lakes and streams, it is best to keep them in an unheated tank. They become stressed at temperatures in the 80's and may die if the tank reaches over 90?F. The small size and ease of keeping tadpole madtoms should make them amenable to captive breeding. To my knowledge, no one has yet accomplished this. It could be a challenge for someone interested in breeding catfish. In March of the second year I had them, I thought my pair were going to spawn. The tank temperature had dipped down to the low 60's in January and February and was approaching 70 by mid March. I had been feeding them heavily with live shrimp and guppies as well as pellets. At dusk the male started cleaning a ceramic pipe in the tank, he alternated between cleaning and swimming with the female. The fish would swim around the tank with the male slightly behind. He would rub against the female and nudge her belly and when they got close to the ceramic pipe he would try to get her to enter. Eventually she went in too, and also seemed to be cleaning the pipe. I never saw any eggs, and unfortunately the male died during a heat wave when my air conditioner broke. I have hopes of trying again after my next collecting trip if I'm lucky enough to find more tadpole madtoms.

I hope I have sparked a little interest in the keeping and propagation of these reclusive catfish. Their ease of keeping and grace while swimming will quickly make them some of your favorite fish too.

This article can also be viewed on the
Minnesota Aquarium Society web site. As published in Aqua News January/February 1997, A Publication of the Minnesota Aquarium Society

Photo Credit:
Konrad P. Schmidt from the The Native Fish Conservancy at



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