Florida; land of flowers and koi predators

By John Hawley

(reprint from KOI USA; Nov./Dec. 2005 issue)

Florida, is Spanish for “land of flowers” and for koi hobbyists it also represents a land of abundant predators. “I never had a need to keep koi,” Jan Brown, North Florida Koi Club president and master gardener noted about her days before koi keeping. “I wanted to grow water lilies. I did grow water lilies. I also grew designer mosquitos and here’s where the long, slippery slide into koi keeper begins.” Along with the flowering foliage, water gardens and koi come predators, many that are found elsewhere in the United States and notable exotic invasive species especially in South Florida.

The Great Blue Heron may be one of the best-known koi predators, which have an interesting history of their own. A century ago, herons nearly disappeared as a result of hunters killing them to harvest their plumes for women’s hats. They made a dramatic comeback from near extinction in part due to the proliferation of koi in hobbyist ponds. The heron has religious significance in Japan dating back to the Heian period (700- 1100 A.D) and the Shinto Sagi-mai or White Heron Dance as it is also known. The dance is still performed today by dancers, in heron-shaped costumes.

“Koi are large fish but it seems to be a game for the herons to spike them in the head, often resulting in death by blunt force or a secondary bacterial infection invading the wound,” Doug Ward, Tropical Koi Club’s former vice president and aqua-culturist wrote.

While they may harm koi, harming these birds is strictly prohibited via numerous laws including the Migratory Bird Treaty Act, which was entered into with Canada, Japan, Mexico and Russia. “Yesterday the netting over one nursery tank was removed to enable routine maintenance,” Joe White, Florida East Coast Koi and Water Garden Society president and AKCA director wrote. “In the evening, I realized I had not put the netting ring back over the tank and hurriedly laid it on the tank with minimal fastening. In the morning this visitor attracted attention by its loud clucks and sounds of thrashing as it tried to escape from under the protective netting. The bird had successfully maneuvered his way into the tank through an open area. A dead apparently regurgitated, three-inch koi was floating on the water surface. Mr. Green Heron flew away once freed from the tank’s enclosure. Hopefully the bird will breakfast elsewhere from now on.”

Around Florida, such stories are nearly as common as citings of these magnificient predators themselves. “I lost four of my oldest and largest koi,” Frank Scanlan wrote. “They were about five years old and the largest probably 15 plus inches were lost to a blue heron that was frequenting our pond in Coral Springs, Florida. I ended up running several monofilament lines randomly across the top of the pond about three feet above the surface. I haven’t noticed any fish missing since.” A watchful eye in the Southeastern United States is always fair warning for those wishing to keep their fish predator free.

Egrets a relative of the heron also enjoy Florida koi as do a variety of other wading and diving birds including spoonbills, ibis, storks and anhingas. “For coastal residents the list of koi terrorists include the full gamut of Atlantic and Carribean/Gulf sea birds, which are fully capable of munching on a medium sized koi, Ward wrote. “A couple of pelicans could clean out a pond in minutes and leaving nothing but a buuuurp! Gloria Estephan can explain that better than I. She got cleaned out at her place.”

There are plenty of other classes of predators such as reptiles that threaten koi around Florida ponds. “In come the snakes,” Ward wrote. “Brown water snakes, moccasins, red rats, Florida kings and our vast collections of exotics (semitropical South Florida) ranging from pythons and boas to any other snake found anywhere in the world. All snakes are capable, agile swimmers and like the taste of fish.”

Yet, do snakes actually cause much concern for Florida koi hobbyists? “I found out snakes enjoy koi as much as herons,” Brown wrote. Several other koi hobbyists in Northeast Florida reported problems with snakes. “We had recently stocked our pond with small koi, and Bill, my husband was out by the pond when a brightly colored snake slithered out from behind some rocks and dove right in after a fish,” Dianne Cassidy said. “Up and out of the pond came the snake with the fish that was too big for it to swallow. Bill took after the snake that proceeded to leave the koi flapping on the bank.” The fish survived and the snake took off down a storm sewer to hunt its quarry elsewhere. Sarah Schllesinger, a First Coast Koi, Goldfish and Water Garden Club member, also did battle with a snake living in one of her several ponds. After numerous small fry went missing she identified the culprit that was sharing the pond one-day while she cleaned the submersible pump and filter. That snake’s koi consumption ended that afternoon. Chris Smith, another North Florida proud father of two young children and numerous koi was so alarmed by snake eggs found under his pond waterfall that he poured a concrete slab around the entire structure and sealed the crevices to prevent any further encroachments of the natural order.

Some of the area predators are warm and fuzzy mammals, which include raccoons and even bobcats. “Raccoons are expert fisherman,” Ward wrote. “Our entire cichlid facility is covered with chain link and electrified at night!” There are some other sneaky varieties of predatory mammals that can clean out a koi pond population quickly. “We ruled out all the usual predators, raccoons, cats, small boys,” Brown wrote. “I was convinced we had been found by an otter. My husband, Doubting Paul, was not convinced. We tried beefing up the netting, lights, electric fence and the ultimate last resort…a radio tuned to a 24-hour religious station. I now have a great affinity with Carl the grounds keeper in the movie Caddy Shack. Remember Doubting Paul…he remained not convinced until the morning he checked the trap we set to find an otter with koi on its breath snarling at him.

Great, I thought, got rid of that problem. I restocked which was the most fun of the whole ordeal, upping the quality of my koi. There was nearly a year of calm at the old pond until another swimming weasel found me. These otters, by the way, have to travel over two miles from the nearest large body of water, up a very shallow creek to get to my pond. The creek is so shallow they must walk the last half-mile.

This time, the survivors went to board at another club member’s pond. They stayed there for 8 months. In the mean time we tried trapping without any success. When we figured it was safe to bring them back I was so happy to see them back home. So was an otter. It took 10 days for him to find them again – even with two surveillance cameras with interior monitor, a motion and heat sensing flood light with an interior alarm.

In spite of the indignity I am sure the surviving koi are suffering, they now have to share a 1500 gallon pond with the goldfish the otter didn’t eat after we moved the koi the first time. Now the pond is covered with heavy gauge hardware cloth held down with steel spikes driven in the ground. Concrete blocks sit on top of the edging. It’s a koi maximum-security prison. Sing Sing for Sankes, if I had any left.

I go down to the empty pond and admire the plants and enjoy the sound of running water…and I plot. Maybe a steel trap there…a tiger pit over there…electric plates.”

The cosmopolitan nature of the South Florida human inhabitants is matched only by their wildlife variety. “In South Florida we probably have the most diversified collection of Koi slaying predators in the United States,” Ward wrote. “Southeast Texas would be a close second.

Alligators are a common predator in the western sections of Southeast Florida and the eastern areas of Southwest Florida where the Everglades and mankind are attempting to see ''whose territory'' it really is! Turtle species include alligator snappers, soft-shell and sliders, all of which are fish eaters. I have sliders in my pond and should a fish get ill, and slow down, the sliders will have him in a second. Don’t keep turtles and valuable koi together unless you have a large pond. Mine is 28,000 gallons and the new one is 60,000 so everyone has some space to co-exist. The turtles came on their own, as did the walking catfish. I did not put them there.

We also have lots of iguanas of various types and they are all fast swimming, fish eating, machines. I couldn’t figure out what was doing them in until Todd Hardwick saw the bite on a fish. I lost several large Koi to a big one a few years back and finally had the great pleasure of blowing him off the fence with a shotgun. It was nearly six feet long. I suppose this makes Florida seem like a jungle in the Amazon and in some ways it can be,” Ward concluded.

Thus, remember when you visit the land of flowers there are also koi predators in those bushes!

Contributing writers: Jan Brown, Doug Ward & Joe White.