Mixing albino corys and pigmented corys influences their movement behaviors

[bekateen]

Svitačová, K., Horký, P., Valchářová, T., & O. Slavík. (2024). Pigment matters: Behavior and lateralization of albino and pigmented fish (Bronze Corydoras) in aquaculture. Applied Animal Behaviour Science. DOI: 10.1016/j.applanim.2024.106205
https://doi.org/10.1016/j.applanim.2024.106205
https://www.sciencedirect.com/science/a ... via%3Dihub

Highlights

• Variations in pigmentation affect locomotor activity, exploratory behavior, hiding and lateralisation.
• The behavior of pigmented and albino fish phenotypes differs
• Albinos are more likely to face reduced welfare conditions

Abstract
Animal welfare science recognizes fish as sentient beings capable of experiencing pain, stress, and various emotions. As social interactions and mutual relationships are essential for fish welfare, the social environment in aquacultures is important for fish welfare. Pigmentation influences fish social behavior, e.g., communication and/or shoaling behavior. We investigated how pigmentation and shoal phenotypic composition affect locomotor activity in relation to feeding, exploratory behavior, sheltering and lateralization in holding tanks and Y-mazes in pigmented and albino Bronze Corydoras (

Corydoras aeneus

). The fish were divided into three treatment groups: pigm only, alb only, and mix groups. Each group comprised 12 shoals, with a total of 288 fish distributed across 36 shoals, each containing eight individuals. The study revealed behavioral differences between fish with pigmented and albino phenotypes, both within and among shoals. For both phenotypes, an increase in locomotor activity before feeding was followed by a decrease in activity after food consumption, indicating an anticipatory response and a shift from foraging to postfeeding behavior. In the mixed shoals, pigmented fish exhibited greater activity and sheltering behavior than albino fish. Both albino and pigmented fish showed lateralization toward the right arm of the Y-maze; however, in the mixed shoals, the preference for the right arm was not significant. Albino fish reached the shelter at the end of the Y-maze more often; however, in the mixed shoals, albino fish maintained their success rate in exploring the maze, while pigmented fish showed an increased success rate. We emphasize the significance of considering phenotypic variation and shoal composition when evaluating fish behavior and welfare. Such insights can inform the management of practices in aquaculture and ornamental breeding to ensure optimal fish welfare and enhance their overall quality of life.

Keywords: pigmentation, locomotor activity, exploration, lateralization, social environment, fish welfare

[Bas Pels]

I think this is a very interesting, and important question, but looking at the results in the article, I get the idea the albinos are more active, the have less fear.

Although that would reduce their lomnglivity in the wild - less fear means earlier cought by a predator, it also implies the well being of the fish involved is not harmed, as one would expect a hurt fish to be more shy, withdrawn, then an unhurt one.

[TwoTankAmin]

I wonder about one aspect of this. Iy is obvious that nomrmally pigmented fish have black pupil. However, albinos have red pupils. For bottom feeders the eyes are normally places to be able to look up easily as that is where predator may lurk. Their eyes also can see sideways and maybe some to the rear. Of course they also see forward.

What I wonder her is when a nomal and and albino fish look at the same object in the same light, do their brains perceive the same things? What I am asking is does the nature of their eyes matter? Is it possible that albino vision is not as acute as normally pigmented individual? Is it possible that a vision deficiency tends to make albinos less afraid because they are less attuned to visual threats?

Of course, I may be off base here. But I have always believed that the reason we do not find herds of albino fish in the wild, just occasional individuals. The reason for this is likely to be that albinos make easier targets for predators to spot.

[dw1305]

Hi all,

...... What I am asking is does the nature of their eyes matter? Is it possible that albino vision is not as acute as normally pigmented individual? Is it possible that a vision deficiency tends to make albinos less afraid because they are less attuned to visual threats?

I'm pretty sure you are right, albino (anything, and for any reason) have much less good vision then their normally pigmented brethren.

Melanin is involved in the development of the cornea, so no melanin = less good vision.

cheers Darrel

[TwoTankAmin]

I never got beyond my undergraduate degree in Psychology. But, paper of that covered expoerimental psychology. So I understand about variables etc. I also understand the statistical analysis basics. It was this that got me my final job.

So, I tend to look for the uncontrolled variables that might have influenced the results of a study. This one jumped out at me right away. If the albino fish cannot see as well as the others, then the albinos may be less alert to danger and be more likely to behave accordingly.

[Bas Pels]

That could very well explain the albino behaviour.

But in that case, the whole study does not fit as an attempt to investigate the well being of albinos