I have a fish that is staying at the bottom of the tank ...seems to be fine but wont do much swimming lately..

Answer 1

It may help of we knew what type of fish, and more about your tank.

Some fish are naturally bottom fish, so it may not be anything to worry about.

On the other hand, if it's a fish that should be more active, it could indicate:

1) there's a problem with your water quality (ammonia, nitrite, nitrate, or pH) - a 25-50% water change will help with this

2) it's a pregnant female livebearer looking for a place to hide and give birth (this usually resolves on its own)

3) a fish that's being bullied by others in the tank trying to stay out of the way (watch the behavior of the fish and how they interact - you may need to separate the fish, either to another tank, use a tank divider, or return one to the store)

4) it's a nocturnal fish trying to find a dark place away from lights ( provide plants and wood that the fish can hide in/under)

5) it's a long-finned fish that's having trouble swimming in the amount of current in the tank (turn down the flow - there should be a way to do this with most filters)

6) it has a parasite or disease and is trying to conserve energy (will need more info to determine this)

Answer 2

my fish do that at night do u keep ur night on all night