NANFA-- Freckled Madtom observations

Denkhaus, Robert (DenkhaR_at_Ci.Fort-Worth.TX.US)
Sat, 12 Jan 2002 12:21:40 -0600

Last June, I happened upon a herd of young of the year freckled madtom. I
kept several and still have eleven total (4 at home in a 30 gallon community
tank and 7 in my office in a 10 gallon tank along with a few slough and
bluntnosed darters). Only about 5/8 inch long when caught, most are now in
the 1.5-2 inch range. For the most part, their behavior has been as I would
expect of a bottom dwelling species except for a period of about 2 weeks
when they spent considerable time swimming in the water column. There are a
variety of nooks and crannies for them to hide in and in an attempt to make
them comfortable but still visible, I placed two pieces of clear Plexiglas
(about 3X5") on the bottom of my office 10 gallon. They have made
considerable use of this cover and are still quite visible to observers.
So, I venture to guess that they are seeking refuge under cover and not away
from light (a tactile response rather than phototaxis). The pieces of
Plexiglas are relatively unobtrusive to the viewer to this seems to work as
a means of satisfying the needs of both the fish and the fish keeper.

Recently though, I have noticed a new behavior primarily in the 30 gallon
tank at home. The madtoms are not venturing under cover of any kind and are
instead placing themselves in a vertical position (head down, usually)
amongst the plants. They will sit motionless like this for hours causing
family members to yell at me to come get the dead fish out. A friend has a
slender madtom that exhibits the same vertical behavior but is squeezed
between a log and the glass so I see that as a tactile response. Has anyone
else seen anything like this?

Lastly, one of the madtoms in the 30 gallon is significantly lighter than
all of the rest. It still has the definitive dark edge on the anal fin but
is so light in color over the rest of the body that I would call it
leucistic. Is this phenomenon known in madtoms?

Rob Denkhaus
Fort Worth Nature Center & Refuge

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