As of the latest patch they collect pearls when you bite them.

P. E. A. R. L. S. That's all you need to know about this amazing creature.

The tek cave update gave the anglers the ability to gather pears, according to the wiki

Very useful for exploring underwater caves

- Main use is after tamed they will attract more anglers which can be harvest for gel
- Secondary use would be a mobile underwater tame that also has a built in light
- Lastly they can be harvested for gel which tames Manta's

(Angeler gel is the longest burning fuel source at 6 min per gel)

They get a lot of silica pearls when you attack the shells with it.

As of the recently, anglers collect pearls. Ranging from around 40 pearls and up on official servers per bite, melee affecting amount (melee mutation = main goal)

Best for harvesting silica pearls after patch v257.

Need a lot of pearls ? ... Then you really want a lightbulb fishy :)

Use a fish basket in abberation to to take them to different water areas

This tame has a couple very nice features and a few drawbacks.
It collects pearls very well by biting them. I get about 50 per bite. You also don't have to get off your tame to collect pearls, which can save you some headaches.
This tame has fairly good speed and the stamina regenerates quickly.
When attacked by an electrophorus, the shock does not dismount the player but does momentarily prevent the angler from attacking.
This could be useful in passive taming the eels, as well as preventing many untimely deaths.

Drawbacks: it has a very small attack range and area of effect. It also has pretty low damage output. It is nearly useless at attacking anything larger than a mega piranha.

This creature is a pain in the neck to tame, but is a near magic solution to running out of pearls.

Put a baby angler in a fish basket and it instantly grows but can’t get imprint

Can harvest pearls incredibly well, so it basically now is the most necessary thing in the game to tame later on.

No saddle required

Makes getting pearls sooooo easy. If you need electronics, get an angler.

After the update these things are crazy for silica. Just make a small underwater cave base near one of the big caves and collect all of the silica. You can get 50 pearls from one node if you pump melee. Just watch out for eels

Not sure if it's a PC thing but eels and jellys can knock you off on Xbox and kill your little lite brite. However they are amazing at getting pearls in the little river on Ragnarok. Haven't tried going after the black pearls yet.

AMAZING pearls farmers. Made SE pearls runs pointless if you have a solid island/center server. This is a must have for pearls/electronics.

An essential tame for any tribe. This animal makes pearl gathering a breeze. There is no saddle required. Just grab on and zoom away. Bite pearl nodes to gather them.

You can use basket for transfer them to pearls spots on Aberration