of their weight at least once per day during the growing
season. Avoid feeding more than 35 pounds per acre per
day in hot weather unless emergency aeration is available.
Feeding allowances must be increased as fish grow. Often
this is done by feeding as much as the fish will eat each
day without leaving excess food floating on the water.
Alternatively, standing crop weight can be estimated
weekly to make appropriate adjustments in the amount
to feed. Estimate crop weight by removing a small sam-
ple of fish, weigh them, and multiply the average weight
of individuals in the sample by the total number of fish
present in the pond. Catfish held over winter should be
fed sinking pellets at about 1 % of their weight every 2
to 3 days when water temperature is below 65 F (18
C). Feeding rates should be reduced by 50% or more dur-
ing very hot weather (water temperature > 85 F) and
on rainy or overcast days. However, if aerators are
available and fish are to be commercially produced, they
should be fed to near satiation. Otherwise, fish will grow
too slowly and return on investment may be too low to
be profitable.


 Disease and Pest Control

 Catfish are susceptible to a large array of parasites and
disease organisms, as well as being affected by a host of
other plant and animal pests. In many cases, healthy fish
may be resistant to or tolerant of pathogenic organisms
if poor water quality and stressful conditions are minimal.
At the other extreme, some catfish diseases may be highly
contagious and debilitating, including those that directly
cause or contribute to fish death. Other organisms that
are not as intimately associated with the fish, such as
aquatic plants and algae, may contribute directly or in-
directly to poor fish health under adverse conditions.
 Because of the variety of diseases and pests that af-
flict catfish, and the variable conditions with which they
may operate, comprehensive and uniformly-applicable
recommendations for their control cannot be made. The
best way to ensure good fish health is to prevent un-
favorable biological conditions from developing, by
carefully monitoring all aspects of an aquaculture system,
and to quickly isolate, identify, and properly treat any
disease or pest problems that arise. A successful manager
becomes familiar with procedures of identifying, prevent-
ing, and/or treating common pest agents and consults
with diagnostic laboratories or specialists when dealing
with unknown problems. Be sure to check local regula-
tions governing the use of chemicals when treating culture
systems with herbicides, pesticides, or medications.
 For more detailed information concerning disease iden-
tification and control, consult Florida Extension Circular
716, "Introduction to Fish Parasites and Diseases and
Their Treatment."


Diseases and Parasites

 The large number of microscopic diseases and larger
parasites that infect catfish range from those that are
relatively benign and generally not harmful under nor-
mal conditions, to those that cause high mortalities and
have no effective treatments. A good disease management
program consists of precautionary measures to ensure
clean water and healthy environmental conditions. Stress
plays a major role in lowering the resistance of fish to
pathogens, and all factors that may contribute to stressful
conditions must be kept minimal. These include main-
taining adequate oxygen levels, avoiding extreme
temperatures, and handling or moving fish as little as
possible. Chemicals should be used to treat disease out-
breaks only when preventive measures have failed, and
it is essential that appropriate medications be ad-
ministered in proper dosages for treating specific diseases.
For this reason, early detection and correct diagnosis of
disease organisms is imperative if chemotherapy is to be
successful. Some of the behavioral signs that may indicate
a possible disease problem include: (1) a reduction or
cessation of feeding; (2) erratic or lethargic swimming;
(3) schooling just below the surface; or (4) swimming or
scraping against the substrate or objects in the water.
Physical signs that diseased catfish may exhibit include:
(1) excessive mucous production; (2) abnormal colora-
tion (lighter or darker, grayish or bluish, etc.); (3) ero-
sion or fraying of the fins or skin; (4) sores, hemorrhages,
or unusual growths on the body or fins; (5) swollen,
eroded, or pale gills; (6) a swollen abdomen filled with
a cloudy, clear, or bloody fluid; or (7) bulging of the eyes
(exophthalmia). If an infectious disease or parasite out-
break is suspected, quick action should be taken to
isolate, identify, and treat if necessary. Some individuals
and laboratories diagnose fish diseases and recommend
treatments, but unfortunately there are few diagnostic
centers in Florida that provide these services. If diseased
fish are to be sent to a laboratory for inspection, live fish
showing symptoms of the disease should be selected and
shipped alive in cooled bags or packed freshly on ice. Be
sure to notify the laboratory that you are sending fish
and give them any necessary information that may be
helpful in identifying or treating the disease.
Weed Control
 Excessive algal blooms or rampant growths of aquatic
plants can be detrimental to catfish by causing oxygen
depletions, and may impede harvesting and reduce
available habitat. In Florida, exotic plants such as
hydrilla, water hyacinth, and water pennywort can
become extremely dense and cause acute problems. A
moderate growth of aquatic weeds generally does not pre-
sent a major problem in catfish ponds, but dense infesta-
tions should be avoided. Weeds that become a nuisance