Hi ghent_3rd
It's hard for me to make a comparison between corys and danios because I don't know much about danios.
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But, I can describe what I have seen my corys do. Perhaps that will give you something to think about.
I have been raising bronze, albino, pandas and a few sterbai, and from what I see, they are most active when they are young and settle down a bit as they get older. My mature corys might make a run or two up and down the glass, or zip across the length of the bottom, but then they gather together and spend some time sitting. Then they might sift through the sand for awhile, then sit some more.
The juveniles are entirely different matter! They are kept in 20 gallon grow out tanks, with mostly their own species present. While they are somewhat sedate in the daytime, come early evening they start swimming all over the place. Up, down and crosswise on the glass they swim. Sometimes one will shoot up to the surface for a gulp of air and that will start them all off. One after another they go until it looks like a fireworks display. They are apt to keep this up until I turn the lights our and go to sleep.
Of course, not only are these corys immature and like kids they are playful, they are in schools of a hundred or more, which could well make a difference in their behavior. Also, in proportion to their size, the adults do not have the space to get up to the relative speed that the young ones can, and there have to be fewer of their own kind in the tank, which might make a difference too.
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