Anglerfish live in the deep sea and lure prey with a fishy growth on their head akin to a fishing reel. What characterises the relationship of two anglerfish?

Explanation

Anglerfish live in the deep sea and lure prey with a fishy growth on their head akin to a fishing reel. But they also have a special mating tecnique. The females have a growth on their body, which looks like a parasite. This is actually the male. The small anglerfish-males are born without a digestive system so when they are hatched, they have to quickly find a female. When this happens, he latches up to her and releases an enzyme, fusing the pair down to the blood-vessel level.