Magnetic fluids (ferrofluids) consist of magnetic nanoparticles (diameter ~10nm) which are dispersed in a liquid, often with the use of surfactants. They were first developed by NASA to address the unique requirements of moving liquid fuel in microgravity conditions. With a help of a holographic optical tweezers, interaction of magnetic nanoparticles with strongly focused laser beam was observed. When the light intensity was high enough, magnetic nanoparticles were removed from the beam center and they formed a dark ring. Creation process lasts less than 330μs and cannot be observed precisely even with ultrafast camera. Such rings exist when the laser beam is affecting the sample and disappear (with a lifespan of 10’th second range) after the laser is switched off. Moreover, when several rings are created simultaneously, complex interactions between them can be observed. In this work, the results of our experiments will be presented with hypotheses about the physical background of such a behavior.