Fuel indicator problem

I have 1996 honda civic cxi 1.6L (109 000 kms). My fuel indicator needle moving up/down quite frequently like when I'm driving in "normal way", the needle drops down a bit and a few minutes later it goes back up again. My fuel consumption doesn't change and my car hasn't been losing power. Can you suggest what might be wrong with my car and is it expensive to fix it? and would it affect my car's performance?

thx

fuel sloshing around in tank?

it's like my fuel indicator goes erratic