The general rule is that one should change around 25% of the water at a time, thus all you need do is leave your fish in the tank and siphon out 25% of the water, and then replace with dechlorinated water of the same temperature. If you are cleaning a bowl, then it is more common to clean the entire bowl; in that case the fish maybe be placed in a bucket or cup.
If they are in a tank, make sure they are fed and the water is clean. To clean the tank, remove the fish and put them straight into another source of water. Remember if your fish is salt or fresh water. If the fish is in the sea, river or pond, its best to leave it. If the fish is on land near a water source, replace it in there. If it is nowhere near a water source, I have no idea how it got there. You would have to leave the fish then. Sorry if this answer is vague, because your question was as well.
you should have clean water in it and try to keep it as clean as possible
when the water starts to get dirty if it is a bit dirty then leave it when it starts to get really dirty clean the filter and your fish tank
you should be at least 20% of the water each time you clean it and you should do alittle more each time
you should change it every week so it will always be clean.
Keeping the water clean in your goldfish aquarium will not only make your fish more likely to spawn but will also greatly improve the health of your fish and any potential fry, so yes you should keep your goldfish's water clean for them to spawn.
when you clean a fish tank you should only do a 5 or 10% water change. You should wipe any algae off the glass, filter of objects in the tank using a new cloth as any soaps that get in the water will kill the fish. After this the water may be cloudy but the filter should clear this within a few hours. You should never do a 100% water change as this much change will overwhelm the fish and could kill them.
You should clean a fish tank regularly with water changes of at least 50% each week along with cleaning out any waste or uneaten food, and using an algae scrubber to clean the sides
weekly 10 - 20% water changes
It is always best to clean them as soon as possible, they should be put on ice or frozen soon after they die. You can freeze them and clean them when they thaw, but for best results clean them, then either use them that day, or freeze them..Even frozen fish should be used within four months of catching them. Never leave fish out at room temperature for more than 30 minutes.
you should never clean your fish tank with washing -up liquid or eny thing like that only a sponge that is new and water
leave it out of water.