I have a new fish and the instructions say to change 1/4th of its water weekly. I am wondering how to do this? I only know how to clean the whole tank. Also, i noticed that the fish very often just swims under the filter with its head facing the glass and just stays there, im wondering why it does this.How to change the water of my fish? and why does my fish stay under the filter?As the previous poster stated you can get a siphon. If it's a smaller tank like a 2.5 gallon or a 5 gallon and you can't get one of those awesome self starting siphons to work go ahead and get a siphon hose. Don't start it by mouth, though. Fill the tube completely with water in the bathtub, plug up both ends making sure it's COMPLETELY filled with water. Keep a bucket on the floor and with thumb still plugging both ends put one end of the hose in the bucket and one end in the water of the tank. Once you get the one end submerged in the tank you can take your thumbs off it and water goes into the bucket. You have to make sure the bucket's lower than the tank though.
As for the fish chilling under the filter.....depending on what kind of fish it is it might be because he doesn't have anything to hide in. If you don't have any of those cute little caves and such for the fish to hide in he starts trying to find stuff to hide behind.
That's my best guess based on limited information =PHow to change the water of my fish? and why does my fish stay under the filter?what fish do you have? how big is your tank? how long have you had your tank?
buy a siphon to remove the water or do whatever you do to remove all the water but just remove less
