Yes, rainbow sharks often jump out of the tank. Despite being bottom-dwellers, rainbow sharks are notorious for jumping out of the tank. This is normal behavior for rainbow sharks, but sometimes, it can also be caused by stress or poor water quality.
Because their tanks are usually large, the rainbow sharks likely land back in the water after jumping out. However, if they don’t, they might get injured after landing on the floor, so you should take precautions and get a lid for their tank.
Rainbow sharks will jump out of even the smallest openings. Therefore, you’ll need a good, tight-fitting lid with absolutely no escape points.