What type of relationship is between a male and female angler fish? as in mutualistic symbiotic etc

An example of a mutualism relationship would include the male and female species of the angler fish. Since the deep is such a big place, it is understandable that it is difficult to find a mate. The angler fish works around this by having a different mating system. This system includes the male biting onto the female and fusing with her to provide fertilization of eggs whenever she would need it. This benefits both because the female will have access to the male's sperm when ever she needs it, and the male will have served his purpose of fertilizing the eggs of the female