What is happening to my cories

So I just did a 40 percent water change and right after, the cories have been surfing the glass and bumping into each other. They do this for a few minutes then calm down for another minute or so and repeat the same thing over and over again.

 

40% is a large water change. How many gallons is your tank, and how often do you do water changes? (Are they always 40%)

You should check your water parameters as well...this would help you see if you disrupted your cycle and caused ammonia spike.

 

They could be triggered to.mate, but moremlikely is they are sinply adapting to.new water.

 

They're probably stressing, I had two who did the same thing, 1 died.

 

Mine do this every water change. Ive taken it as normal as no ill happenings result from it. They return to normal after a day or two.

Its even more pronounced if you have kuhlI and java loaches... they go bonkers because of it