Stark, crowded aquariums lead to violence
Fish who live in cramped and barren aquariums are more likely to get violent, a new study from Case Western Reserve University has found.
The scientist behind the study, biology professor Ronald Oldfield, hopes his findings benefit the 182.9 million ornamental fishes in the United States. (Animal welfare proponents, he notes, often overlook our underwater friends.)
But, beyond that, the findings of his study could apply to other species as well.
Oldfield, according to a university press release, is the first to scientifically study how the environment of home aquariums affects the aggressive behavior of ornamental fishes. The results are published in the online edition of Journal of Applied Animal Welfare Science.
Oldfield compared the behavior of Midas cichlids (Amphilophus citrinellus) in a variety of environments: within their native range in a crater lake in Nicaragua, in a large artificial stream in a zoo, and in small tanks of the sizes typically used to by pet owners.
The study focused on juvenile fish, so that aggressive behavior related to mating would not be a factor. Also, resources such as food and shelter were removed prior to observation to eliminate direct competition for those.
Along with environment size, Oldfield tested the complexity of an environment and the effects of number of fish within tanks.
The addition of obstacles and hiding places using rocks, plants, or other similar objects can increase the complexity of the aquarium environment. He found that an increase in tank size and complexity can reduce harmful aggressive behaviors, and make for healthier fish at home.
The aggressive behavior he monitored included flaring fins, bites, chasing or charging at another fish.
In environments sufficiently large and complex, fish spent less time exhibiting aggressive behavior. And a more natural environment elicits more natural behaviors, Oldfield said. “This study might help us to better understand how human behavior changes when people are placed in different social environments,” he said.
Among the species that could benefit from Oldfield’s findings, it seems to me, are America’s 2.3 million prisoners (prisonus inmatus) and others held in what are often stark, impersonal institutions that lack visual stimuli, mental challenges, or for that matter tiny treasure chests, mermaids and sunken ships.
Posted by jwoestendiek September 26th, 2011 under Muttsblog.
Tags: agression, animals, aquairums, behavior, biology, case western reserve university, connection, environment, fish, learn, research, ronald oldfield, science, species, study, surroundings, violence, welfare
Comments
Comment from Sarahkate
Time September 26, 2011 at 1:29 pm
This isn’t new (sorry!) there were studies on the violence up to and including infanticide and multiple homicides by rats on rats in overcrowding.
A growing number of people over the last four decades are concerned about overpopulation as one of the causes of increased worldwide human violence (such as in Africa and other third world countries as well as in US). Just sayin’.
Comment from Anne’n'Spencer
Time September 26, 2011 at 6:11 pm
We had a largish (55 gallon) community freshwater aquarium for years when the kids were growing up. There’s nothing in this study that any good fish shop owner or employee, or any thoughtful aquarium owner, couldn’t tell you. We patronized an excellent store (House of Tropicals) in Glen Burnie. They had advice posted everywhere on the habits of the fish, the number that could live comfortably in a given space, the aggression level, the suitability for a “community” tank, the growth expectation, and any other information you could possibly want. The employees were ready with advice on your selections, and they took great pains not to allow anyone to go astray. Any fish store employee who cares will tell you immediately that overcrowding is the #1 problem and will tell you in no uncertain terms that fish do suffer. They’ll also encourage your efforts to set up a healthy, well balanced aquarium where your fish can thrive.
To the best of my recollection, cichlids are feisty, territorial fish. I suppose they’d make a good community for a study like this, but it would be interesting to see the same thing done with more gregarious, community-oriented fish.
Comment from anon
Time September 26, 2011 at 8:46 am
Way many years ago got into an arguement with a department store employee on the inadequate space provided for fish being sold.
Suspect she thought I was loony.