Information Central (c) Larry Larsen
Wild from the field
Once in a while, I see an unusual-appearing fish, and not being a
biologist, question such markings or growths. I have also received emails from supporting members and others along with attached photos of
peacock bass with unusual markings. One wrote, "I believe that this could be a fungus or perhaps a "hybrid" that cross-bred with another
species of peacock bass." He went on to ask me if I had seen a similar fish with such markings? I told him that I have indeed seen a couple of
fish (bottom photo) like this, and I too, thought it looked like a fungus or some kind of growth spread all over the body of the fish. The fish that I
have seen with the markings were caught on the Nhumunda River, while the fish in the first picture was caught on the Upper Uatuma River.
I did send the two photos to two different biologists who are
knowledgeable of peacock bass and neither one was sure about what could have caused the unusual markings. Paul Shafland, who heads us
the peacock bass program in Florida, suggested that the growths are probably not a fungus, but may be a bacterial infection. "The wart-like
protuberances may have a viral origin," he said, "but that is highly speculative." Another fisheries biologist who professed to not be an
expert in diseases, called it "bizarre" and commented that he had never seen anything like it.
Paul forwarded the photos on to Greg Vermeer, a fish pathologist, who commented as follows: "I can't be
too sure from just the pictures, but metacercarial cysts are a possibility. These are usually in the internal
organs, but may also be on the skin. Ideally, I would like to see some affected skin to confirm the diagnosis
, however, cysts caused by parasites seem to be the most likely cause. Here is some more information on
metacercarial cyst. Certain types of parasitic worms (digenetic trematodes) live in the guts of birds, fish,
mammals and amphibians. These adult worms produce millions of eggs that are eliminated with waste and
enter the aquatic environment. When these eggs hatch, the larval parasites infect a mollusk, usually a snail
. In the snail, cercaria form which leave the snail, find a host, burrow into the skin and form a cyst in the
skin, flesh or internal organs. Often cercaria don't find the right host and penetrates the skin of the wrong
animal." We thank the 3 biologists for their time and comments. If any of our members have seen similar or other unique markings, please let me hear from you.
I received another query about a similar fish who asked if this
was a different peacock (species) or just a color pigment (abomination). He mentioned that the fish was actually 14 K
gold in color. It weighed 21.4 pounds on a digital scale. I have seen a few fish with similar color schemes/patterns and
I think it is an intergrade (cross between 2 species). It has the pattern of two or more different species. I've also had
pics of strange 5-bar fish from Miami waters sent along with the question, "Do you think this is a genetic mutation being
passed on or a subspecie?" Again, that fish may have been a Cichla intermedia or "royal" peacock. It did not appear to
have black cheek "splotches" like many of the other species of peacock. Nor did it appear to be a Cichla ocellaris, which is
what we call butterfly peacock in FL, but it might be a hybrid cross or subspecies. Several were defined by biologist
Kurlander in scientific fishery papers in 2007. It may be a fish
thrown into the canal by an aquarium owner that found it to be too big for their tank. Aquarium wholesalers
do sell several species from various waters, and not all of them are from the areas where the Florida Wildlife Commission got their initial stocking brood.
I've also received images of peacock showing an anomaly in the butterfly peacock, such as one from the Yatua
tributary of Venezuela's Pasimoni River. The middle spot is missing altogether. Another shot, such as this 4-Bar
Florida peacock bass crossed my desk as well. There are multitudes of combinations of colors, patterns and
contrast in his many slides of our favorite fish. Exotic fishes are
fishes from other countries that have been introduced into Florida intentionally or illegally by man. Thirty-two (32) exotic freshwater fishes
are currently reproducing in Florida freshwaters, more than any other place in the world, and some of these fishes have become very successful
in terms of their range extensions and abundances. All but one of these fishes (the Butterfly Peacock Bass) were introduced illegally as the result
of individuals releasing unwanted aquarium or food fishes, and/or the
flooding of aquaculture ponds. Since nearly all of these exotic fishes are tropical species native to Central
and South America, Africa, and Southeast Asia, the most important factor limiting their range in Florida is their intolerance to low water temperatures.
Editot's Note: Tips reprinted with permission from PBA's "The World of Peacock Bass" monthly eZine.