They are possibly down there because the water is too warm in the higher levels or it could simply be that your water is bad and needs changing. My advice is to do a large (80%) water change ASAP then remember to do at least a 50% water change weekly.
Maybe the water is too hot or needs changing. Fish can go to the bottom for either reason. If the fish are not tropical and the water is above 75F heat could well be your problem if not then your problem is bad water conditions. My advice is to change the water ASAP. Then read the following basic rules of fish keeping and follow them. :- 1 inch of fish needs a minimum of 1 gallon of water. :- Every fish tank needs a continuously running cycled filter. :- Every fish tank need at least 50% of its water replaced every week.
Goldfish have central mouths. They are not bottom feeders or top dwellers. This means they should stay at the center of the tank. It also may mean that your fish are sick, or they could just be scavenging for food in the gravel.
The fish has swim bladder disease. This can be helped, however not cured. I had the same problem with a fantail goldfish, this fish has been alive for three years with swim bladder, and is still living. If the fish does not get help, eventually it will die. The way to help this disease is to give a frozen pea to the fish, and make sure it is peeled. If this is a large fish, one pea will not work. Two peas will do the trick, but smaller fish only need one. Hope this helps!
Maybe the bottom of the tank is cleaner? You should go to a place that sells fish and ask them. Good luck:)
Most likely because they are dead or are scared of someyhing above.
Most of the time its because they are resting. But if it stays there to long its probably dead
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Because there is more oxygen at the bottom of the tank. Not for our type of lungs but theirs
they just settle at the bottom of fish tank
If your fish food is staying afloat for a week it is most likely because it is just buoyant and you have overfed your fish. Feeding your fish less will reduce fish food staying afloat as well as help keep your fish and tank healthy.
gravel
I suggest that you learn more about your fish in your aquarium. One of your fish might be a bottom sucker which means that they eat all of the dirt on the side or bottom of your tank. If one of your fish are bottom suckers, that's probably the reason why your aquarium is clean. If none of your fish are bottom suckers, than somebody must be secretly cleaning your tank for you.
It dies
Fish eggs, fish sperm, mold.
food flaots
You simply take any fish and drag it to the bottom of the tank and then drag it up (fastly) and it will go soaring!
ummm your fish is dead....sorry.......
Could be anywhere.
for decoration use.
Flush them down the potty.