While not overtly useful, the angler is a particularly vertile early game ocean mount, it has a built-in light source which is infinite and exceptionally useful, it can collect silica pearls and can attract angler fish for gel farming. Although it is unable to defend itself against the larger predators of the ocean it is capable of outrunning many of them and it does not require a saddle, they can be be found all over the ocean, however the main drawback is that they are deep-water fish and the lengthy tame time means you are vulnerable to deep-water predators without a mount. It's not particularly safe to use underwater compared to some of the other durable mounts like the megalodon, which is easier to tame at a lower level.
Good for use as lanterns if you live on the beach.
Be really care when knocking these things out from a distance! Unfortunately they don't look knocked out when they are so continuing to shoot darts at them can be an easy an unfortunate mistake to make.