No. It Can Be Very Smelly In Fist Environment's Sometimes
It is the decomposition process because when they are in the water the dont smell but when they exit the water they start smelling
they dont they are fish they breath under water
as you observe that when human die they stink when kept for a long time they don't stink if their organs are removed or they are dipped in salt water, it is same for fishes too.
Because fish have gills,giving them the ability to breath under water and divers dont.
This maybe is because old rotted food is in your bettas water.
dont put a fish in water
i suppose mostly fish and other animals that can breath under water but i dont think they survive.
Whales and Dolphins are born under water and aren't fish.
dont you mean saltwater fish?
fish dont drink salt water they just feel it
They don't have eyelids and the reason why people blink is because we have to wet our eyes,but, they live under water so they're eyes are always wet.
i recomed the gold fish or well i dont know what its name is but come kind of cleaner fish that sticks to walls that would keep the dirt and muck out of the way and under control