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Group behavior in goldfish


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A couple years ago 6 goldfish were born from the same batch of eggs and from the same female in my outdoor pond. 4 are black, 2 are orange, and one is yellow. They are all the same size. As they swim, the four black ones always stick together (usually touching or no more than a couple inches apart)—same for the 2 orange. The yellow one is usually by itself.

 

My question is, how does a goldfish know what color it is? I couldn't find a quick answer online.

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Perhaps.

 

Let me think about it...

 

If this is something that has never been explored then I think it would make an interesting problem to solve. For example, if fish under an amber or red light don't school together by color then we'd know it is a visual cue. Otherwise it may be a behavioral cue and fish may not actually know what color they are.

 

I wonder if it is a question that has been answered.

Edited by Iggy
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But does a goldfish have enough intelligence and self awareness to recognize itself in a reflection?

 

"The sense in which animals can be said to have consciousness or a self-concept has been hotly debated; it is often referred to as the debate over animal minds. The best known research technique in this area is the mirror test devised by Gordon G. Gallup, in which an animal's skin is marked in some way while it is asleep or sedated, and it is then allowed to see its reflection in a mirror; if the animal spontaneously directs grooming behavior towards the mark, that is taken as an indication that it is aware of itself. Self-awareness, by this criterion, has been reported for chimpanzees and also for other great apes, the European magpie, some cetaceans and a solitary elephant, but not for monkeys. The mirror test has attracted controversy among some researchers because it is entirely focused on vision, the primary sense in humans, while other species rely more heavily on other senses such as the olfactory sense in dogs."

http://en.wikipedia.org/wiki/Animal_cognition#Consciousness

 

According to Wikipedia they learn with whom they should swim:

 

"Fish use many traits to choose shoalmates. Generally they prefer larger shoals, shoalmates of their own species, shoalmates similar in size and appearance to themselves, healthy fish, and kin (when recognised). The "oddity effect" posits that any shoal member that stands out in appearance will be preferentially targeted by predators. This may explain why fish prefer to shoal with individuals that resemble them. The oddity effect would thus tend to homogenise shoals.

 

One puzzling aspect of shoal selection is how a fish can choose to join a shoal of animals similar to themselves, given that it cannot know its own appearance. Experiments with zebrafish have shown that shoal preference is a learned ability, not innate. A zebrafish tends to associate with shoals that resemble shoals in which it was reared, a form of imprinting."

http://en.wikipedia.org/wiki/Swarm_behaviour#Marine_life

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"Fish use many traits to choose shoalmates. Generally they prefer larger shoals, shoalmates of their own species, shoalmates similar in size and appearance to themselves, healthy fish, and kin (when recognised). The "oddity effect" posits that any shoal member that stands out in appearance will be preferentially targeted by predators. This may explain why fish prefer to shoal with individuals that resemble them. The oddity effect would thus tend to homogenise shoals.

 

 

I think this is very true. I know zebras are know. To do the same thing, do confuse predators such as lions. They tend to be attracted to black and white things. And I think the fish just do what they can survive. You can have a pond with nothing in it, then add a few rocks in a corner, and the fish should flock towards the rocks and stay in that area, in a sense of protection

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I wonder if the 'oddity effect', mentioned in Spymans post, is why humans have colour racism and still tend to striate along those lines due to a persistent evolutionary hangover from our water-dwelling ancestors?

Edited by StringJunky
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Maybe. And then there are exceptions when it comes to interracial couples

Yes of course. I think it's fair to say it's evolving out of us, IF that of-the-cuff conjecture of mine has any truth, which it may well be rubbish. :) . I was looking at it as a broad trend, locating a possible source, rather than an absolute demarcation of specific behaviours, which anything of this nature very rarely is.

 

Regarding the OP, I think we need to ascertain the cognitive faculties of goldfish to see where to start getting meaningful answers.

 

I do a lot of carp fishing for 20 year-old-plus fish - we have the strange habit in the UK of putting them back for them to get old and many are known individually - and they are smarter than most people realise. Their memories are capable of persisting for at least 3 months.

Edited by StringJunky
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