Why do fish float to the water's surface when they die and can they do that while they are still alive?

Question

Do they float because their muscles are relaxed, well wouldn't they relax their muscles to sleep. Please explain. Thanks! (by the way, no I do not have dead fish...only in the icebox...I don't own any pets right now)

Answer 1

they can folat to the top when alive yes mine do it when sleeping, also if they are over fed it messes with there swim bladder so the float untill they pass all the food.

as for when they are dead i have seen many sink to the bottom. i think it is to do with traped gesses that makes them folat at first then when the gass is slowley released they sink.
i think is the same in people who die in water, they float then sink (i remder hearing it on a documenter)

Answer 2

Yes fish can still be alive if they are floating on the surface. However, it's generally an obvious indication that the fish is seriously ill, diseased, and/or is already dead. Either way, if there are other fish in the tank, all sick fish should be removed immediately for (hopefully) treatment and quarantine.
After fish die they float to the surface like any animal, as their lungs and organs are full of air. Then the air expels and they eventually sink, or get eaten by other animals.
If fish are constantly swimming close to the surface, it means they are having trouble breathing and need more oxygen.
You should get a good pet fish management book, or search the internet for some good fish tank management sites.

Answer 3

fish "float" or "sink" by using what's called a swim bladder. It's a sac (bladder) that they can fill with air to make them more bouyant (float) empty to make them sink, or adjust to maintain neutral bouyancy (so they can stay anywhere in between. Submarines have the same setup called a ballast tank which is filled with sea water to submerge or blown out with compresses air to rise. By the way, when fish are dead they rise to the surface because of gasses trapped within the body caused by decomposition, same as people, dogs etc etc.