Why do corydoras swim to the surface?

Where is the best place to purchase swim caps? How heavy is a swimmer? Why does the PSI continue to rise on my filter? What is behind the sides of a pool that is fiberglass with a concrete bottom? How long can your suction and discharge hoses be on an above ground pool? When it rains how much does it fill up your water tanks? What is a sentence of submerge? Do Orthodox Jews swim separately in swimming pools? Between what 2 countries is the baffin bay located? Can you wear shorts and tank top to antioch water park? Is submarine diving safe after scuba diving? How much algaecide do you use for 20000 gallon pool? Where the Cyclone is called as willy willy? Can Alex and ani bracelets get wet? High pH in salt water pool? What causes small air bubble on walls of pool liner? I have some small pebbles that look to be clogging my drain line pump still working but I am concerned about suction Can you unscrew the 8 screws and take off great and try to unclog the pebbles? During the filming of Titanic what was the water temp. for the actors? Insect which shares its name with a game? What can you do to stop people from peeing in your pool?