Generally they tend to move but you may notice that they tend to follow the same path. For example, you move your eye in a certain way, you see the same floater move in exactly the same way. My own experience is that some can get stuck but they will still move eventually. However, some people have very large floaters that are suspended almost in one position which can cause very severe visual problems if not removed.
It sounds like a vitreous floater and you should make an appointment to see an ophthalmologist for a complete dilated exam because sometimes it can be a sign of a retinal tear or detachment or even bleeding in the eye. Usually, it is a harmless thing but there is a small but significant chance of a real problem. - so that's why you need to have it checked out.
MJK MD
Have you been checked for macular degeneration? you may want to have an OCT test. What you are describing is the same thing that my mom had noticed prior to be diagnosed with wet macular degeneration.
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thank ,it has not moved from the spot in which I first noticed it, do floaters sometimes not move ?