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Noturus flavus  Rafinesque, 1818  

here is about 25 species or so of the genus Noturus, commonly called, madtoms, and they of course belong to the same family as the bullheads and channel catfish, the Ictaluridae. The name Noturus means "back tail" and refers to the fusion of the adipose and caudal fins ( in some species ) which tends to give them a tadpole-like appearance.  

Noturus flavus

Noturus flavus


Noturus flavus
- head view

Noturus flavus is commonly called the 'Stonecat' because of its tendency to hide beneath flat rocks in fast flowing riffles and runs among stones on the river bed, where it resides in moderate to large streams.

I have never seen any madtom species in the U.K. for sale in the retail shops, and it is one genus that I would dearly love to have had, at one time or another ( hint, hint, to our American aquarist friends). The nearest I got to them was when the first coldwater darters where brought into this country from the U.S. about 10 years ago (1989) and I purchased the beautiful Rainbow Darter, Etheostoma caeruleum. At the time there were rumours that madtoms had also been imported, but alas not one to be seen. In these days there was no restrictions on keeping the more exotic coldwater species but now echoing that great song of the past, "Times they are a changing " (*see below).

The main talking point of N. flavus and other madtoms is the venom contained in the dorsal and pectoral spines of this genus which can give a very nasty sting, it is a venomous toxin that forms part of the mucus coating on these spines. In some cases this can last a few hours with swelling of the infected area. This of course is a deterrent to large predators to keep well away and is an excellent defence mechanism. Jason Leaman from Pennsylvania talks about a close species in N.insignis and he states that "if you get stung by the Stonecat, the best relief right away ironically is to rub the wound onto the fish (anywhere you won't get stung again). I have never had the sting last more than about 30 seconds. Its really not too painful, however throbs a bit briefly. I don't know how long it would actually last if I didn't use the Stonecats own medicinal value of its oily flesh"

This madtom and others in the same genus have been an ambition to a lot of U.K. catfish keepers to own (myself included) but with a few of them being in the endangered list in their own habitat, and with the U.S. Government and our own Government restrictions, it looks like we will just have the pictures to drool over.

There is now moves afoot by the Government ( U.K.) through the Ministry of Agriculture, Fisheries and Food (MAAF) to impose restrictions on some coldwater species like the above mentioned 'Stonecat', due to the dangers of introduction to native waters and the threat to its occupants through disease and predation. In other words you could be paying up to £30 for a license to keep them. In the future due to the exporters having to implement new guidelines on matters such as health records for each fish, they could become quite rare in the U.K.

Update: As of November 1998 in the U.K.you must have a licence to keep the above species. This licence is now issued free, but does take a few months to process. There has been numerous updates since 1998 so would be better to check this out. For more information log on to the
DEFRA site and also to get a phone number if needed.

The body is slender, and compressed posteriorly; the head and nape are broad and depressed; the mouth is subterminal; eye small to moderate. The pectoral spine is straight; the surface usually only roughened, and lacking prominent serrae. The genital papilla is conical and a ventral apical notch is present. The upper jaw projects beyond the lower jaw. The tooth pad on the upper jaw has a narrow, crescent-shaped extension on each side. The notch between adipose and tail fins are closer to tip of tail fin than to the dorsal fin base. The dorsal fin has 1 spine, (5)6 rays. The upper caudal rays number (27) 29-33(36) and the lower caudal rays (26)27-31(33). Anal rays 15-18(19); pelvic rays (8)9-10; the pectoral has 1 spine and 9-11 rays

Back and side gray, olive, or brown, often with a yellowish cast; postdorsal spot yellow; fins with a pale yellow cast, blotches gray to blackish

This is one of the bigger madtoms growing to a foot in length in the wild, (smaller in the aquarium) compared to most of the other species which grow to between 4 and 5 inches. Not having kept this species myself the data that I have collated points to a large tank ( 4' 0") with a gravel bottom with no heater of course with an external filter and good water movement. They are very nocturnal so plenty of hiding places, large rocks or slate would suffice, they would then venture out at night for feeding, and would be able to be seen with the tank lights off and with one small light on in the viewing room.

As far as I am aware, no madtoms have been bred in the U.K.but some successes have been recorded in the U.S. and Canada. Spawnings in the wild for Noturus flavus takes place in Spring or Summer with higher temperatures to trigger spawning. According to Scott and Crossman (1979) the eggs, which number between 20 and 100 are deposited in a cavity beneath a rock or other structure. The eggs are amber-yellow and are very large, ranging between 3.5 and 4mm diameter, with the whole egg mass enveloped by a gelatinous material. A female stonecat may produce between 200 and 1,200 eggs per year. They exhibit parental care, with the male or both sexes guarding the clutch.

In their native habitat they will feed on aquatic insects and crustaceans. Aquarium specimens do prefer live feeding including glass shrimp, whiteworm, earthworms and bloodworms, but you might be able wean them on to frozen food, shrimp pellets and carnivore flake.

Noturus : Meaning "Back Tail" referring to the fusion of the adipose and caudal fins
flavus: Yellow

Burgess, Peter Dr. The Madtoms N.A.C.G.Sept.1997.
Knopf, The Audubon Society Field guide to North America Fishes, Whales & Dolphins, 1986.
Fishes of Ohio's State Scenic Rivers.
Leaman, Jason; e-mail corespondence: 18/05/07

Photo Credits

Ohio Division of Natural Areas & Preserves


© Birger Kamprath

Factsheet 042

Common Name:
Stonecat Madtom
North America: St. Lawrence-Great Lakes, Hudson Bay (Red River) and Mississippi  River basins from Quebec to Alberta in Canada, and south to  northern Alabama,  northern Mississippi, and northeastern Oklahoma, USA; Hudson River drainage in  New York, USA
22.5cm. (9ins)
05-23°C (37-73°F)    
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                                                                                                           Factsheet 42 = updated December 14, 2018 , © ScotCat 1997-2018 Go to Top