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An angry glare from the family goldfish might not be the result of a missed meal, but a too-humble abode. Fish in a cramped, barren space turn mean, a study from Case Western Reserve University has found. Ornamental fishes across the U.S. might be at risk, all 182.9 million of them.
"The welfare of aquarium fishes may not seem important, but with that many of them in captivity, they become a big deal," said Ronald Oldfield, an instructor of biology at Case Western Reserve. Why, then, has the welfare of pet fishes been overlooked among the scientific community?
Oldfield 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 Journal of Applied Animal Welfare Science, volume 14, issue 4. |
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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 to remove aggressive behavior related to mating. Also, resources such as food and shelter were removed prior to observation to eliminate direct competition.
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. |
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