Obviously the temperature in the rest of the tank is too cold for the type of fish you are trying to keep, try turning the heater up a few degrees or if you do not have one like that replace with a new, bigger one.
It may be sick or shy, looking for a place to hide. If it is pregnant it may be ready to give birth.
Well, not too long. About 25 minutes. It should not be any longer than that. If you want it to go a little faster, you go to to Menu, and click on Options, and then click 2x Speed, or it should say something like that. When I get pregnant fish, they usually take about 20 - 25 minutes for me. But I have it on 2x Speed in the Options Menu.What kind of fish? For most tropical fish their tummies get really big, they don't eat, and they just sit near the heater near the bottom of the tank.
guppies
that is probably were they all meet up or it is too cold
I think you mean without a heater but if you dont the temp for the average tropical fish is 19 degrees celsius to 30 degrees celsius. coldwater fish will survive with a heater if its at a low temp and so can tropical with a heater at a low temp.
No
they do not stay on by glue i am not sure why they stay on but my answer would be they gorw on them.
Bettas do this because they are tropical fish and like warm water. They like being at the top because they breathe air like people. If they are sleeping or relaxed, they will often hand near the top so they can just constantly breathe.
i think that so that they could eat stuff on the bottom or release liquid or droppings
Near the firewall behind the engine, or under the dash near the heater core.
Side of water heater, near bottom.
If yours has one the plug is located near the battery, the heater is located at the back of the block near the egr.
a fish stay longer by muslimninja