Brown Bullhead Catfish (Ictalurus nebulosus)
One of the most common catfish to be found in the fresh waters of the United States, the brown bullhead is relatively unknown as an aquarium specimen. It makes, however, a fascinating and long-living captive. Like most catfish it is covered with a highly sensitive skin as opposed to scales. Taste buds are located within this skin, as well as along the four pairs of barbells around the mouth. The bullhead's reaction to the presence of even a small amount of food in the aquarium is rapid and very interesting to behold. It is quite hardy, thriving in waters with a low oxygen content and able to pass short droughts buried in mud.
Young bullheads will get along with each other quite well, but adults tend to become territorial. These fish to grow quite large (to 18 inches) and thus require spacious aquariums. There is evidence that they recognize one another by scent, this being a useful ability to a largely nocturnal creature that often lives in mud bottomed water bodies. In captivity, however, bullheads quickly give up their nocturnal ways and become active whenever they sense the presence of food. They are, interestingly, able to hear airborne sounds and can, through the use of food rewards, be taught to leave their shelters upon hearing a sound such as a whistle or tuning fork.
As with all temperate fish, breeding is more likely to occur if the bullhead is subjected to seasonal fluctuations in temperature and day length. Both sexes participate in nest building, cleaning the eggs, and in driving off potential predators. Upon hatching the fry school together and follow the male about for some time. It is thought that he might lead them to food sources, but this has not been documented.
Madtoms appear to be miniature bullheads and are actually closely related to them. Most species are less than 5 inches long. Their similarity to bullheads ends, however, with their appearance. Unlike their larger cousins, madtoms are, in general, creatures of clear, flowing streams. As such, they are intolerant of bad water quality and also require a good deal of aeration in their aquarium. They are also more strictly nocturnal than are bullheads but when well-adjusted will explode from their hiding places during the day at feeding time. They really are extremely frantic while feeding. They get along together much better thanbullheads, and so they may be kept in groups. Where legal, madtoms may be collected with a net in their daytime retreats (usually below stones) or in baited minnow traps.