sealPurdue News

August 1999

Study: Aquariums may pacify Alzheimer's patients

WEST LAFAYETTE, Ind. -- Casting about for ways to soothe Alzheimer's patients, Purdue University researchers have found that displaying tanks of brightly colored fish may curtail disruptive behaviors and improve eating habits of people with the disease.

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Nursing Professor Nancy Edwards tracked 60 individuals who resided in specialized Alzheimer's units in three Indiana nursing homes. She found that patients who were exposed to the fish tanks appeared to be more relaxed and alert, and they ate up to 21 percent more food than they had before the introduction of the fish tanks. The average increase in food consumption was 17.2 percent.

The study also showed a decrease in the number of instances and the duration of behaviors such as wandering, pacing, yelling and physical aggression.

One of Edwards' co-researchers will present preliminary findings from the study June 29 in a poster session at the International Conference on Nursing in London.

Edwards says the initial findings suggest that placing fish tanks in nursing homes may help cut health-care costs by reducing the need for nutritional supplements and for medications given to help calm disruptive patients.

"Feeding is often a terrible problem, because the patients are either running up and down the hall, or they're so lethargic that they can't stay awake to eat," says Edwards, who specializes in treating patients with chronic illnesses.

"We thought if we could calm these patients and keep their attention, we could perhaps increase their nutritional intake and decrease the amount of supplements they required. This not only would help reduce the cost of patients' care, but it's also healthier for the patients to get their nutrition from food rather than supplements."

For four weeks before placing the fish tanks in the nursing homes, Edwards collected baseline information on each patient's eating and behavioral patterns. The researchers weighed each patient's food before and after each meal, and patients were evaluated on 29 different types of social interactions and behaviors. Use of chemical and physical restraints also was recorded.

Patients in the first two studies were then introduced to the fish tanks and followed daily for four weeks to collect comparable information. After the four-week assessments, data were collected weekly for six more weeks to determine if the effect, if any, remained or diminished over time. The patients in the third study received the same treatment but were exposed to a picture of a seascape for four weeks before the aquariums were introduced.

"We wanted to see if a simple change in the environment could account for these changes in eating and behavior," Edwards says. "Though we're still sorting through the data, our preliminary findings indicate that introduction of a seascape photo had no statistical effect on patients' behavior. For the most part, members of the control group either ignored the picture or gave it only passing attention."

The tanks of colorful, gliding fish, however, often held patients' attention for up to 30 minutes -- a relatively long time for many Alzheimer's patients, Edwards says.

"I think the combination of movement, color and sound provides a stimulating experience for the patients," she says. "Often long-term care environments do not offer a lot of stimulation, but fish move around in various patterns, so there's enough variability to keep patients' interest."

Edwards says that in addition to increasing attentiveness and alertness in Alzheimer's patients, she found anecdotal evidence that the aquariums also may, in some instances, stimulate short-term memory. She recalls how one woman, who never spoke to staff members or other patients, became fascinated by the fish tank, spending long periods watching the fish.

One day, the woman approached Edwards and asked "Hey, fish lady, how many fish are in this tank, six or eight?"

Edwards, surprised by the question, told her there were six fish in the tank. "Well one time I counted six and one time I counted eight," the woman replied.

"We were absolutely amazed, because we had no idea that this woman could talk, much less count," Edwards says. "We also had a male patient who used to run a bait shop, and he would sit and talk to us about the different kinds of fish and what kinds of bait we should use to catch them. Apparently, the fish tanks stimulated some cognitive things with these people."

Previous studies have shown that pets and animals can stimulate patients and help alleviate some medical problems in the elderly, but applying those findings to Alzheimer's patients presents special problems.

"These patients have to be monitored, because they might step on the cat's tail or pull the dog's hair," Edwards says. "The nice thing about the fish tanks we used is that they are basically indestructible."

The specially designed tanks used in the study were built by Jeff Boschert and marketed through his California company, Some Thing's Fishy. Designed specifically for nursing homes, the tip-proof tanks feature locked tops and unbreakable glass, and a specially designed background that allows the fish to be easily seen by residents who may have cataracts or other vision impairments. The units also can be moved easily from room to room.

Edwards got the idea of using the aquariums with Alzheimer's patients after Boschert contacted Alan Beck, the Dorothy McAllister professor of animal ecology and director of Purdue's Center for the Human-Animal Bond. Boschert offered to donate the tanks for research after reading a book written by Beck about animals and human health. Beck put him in contact with Edwards.

She now is designing a second set of studies to replicate her findings and to further identify the factors -- such as color, motion and sound -- that stimulate patients. She also is working with a researcher at the University of North Korea to replicate the study and obtain cross-cultural information.

The study was supported by Indiana State Department of Family and Social Services Administration, Division of Disability, Aging and Rehabilitation Services. Start-up funds were provided by Sigma Theta Tau, a nursing honorary.

Sources: Nancy Edwards, (765) 494-4015;

Jeff Boschert, (800) 791-3321,

Writer: Susan Gaidos, (765) 494-2081;

Purdue News Service: (765) 494-2096;


Purdue researcher Nancy Edwards is studying how fish may be used to help ease disruptive behaviors by Alzheimer's patients that can interfere with eating and sleeping. (Purdue News Service Photo by David Umberger)
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