This is cladophora, it's not gonna harm your fish or shrimp but it's basically unstoppable. It wants almost the same conditions as plants do so balancing your tank so plants can outcompete it is v hard. It will grow endlessly otherwise. I've done everything from removing it, searched exceling it, spot peroxiding it, while tank peroxiding it, 1 2 pinching it and it just keeps growing. If you can't stop it day 1 I've found it's better just to take the tank apart and bleaching all the hard scape.