They are fiercely territorial and aggressive, attacking anyone or anything that comes near, and are usually found in groups of two to three. Lakelurks have two sets of teeth; a set similar to human teeth and another set of teeth in front similar to that of a piranha.
The fact that lakelurks generally keep together in groups of three to four and they have a high perception make them very quick to find potential prey. Once found they are capable of emitting long-distance sonic pulse waves to stun and confuse their enemies before swiping at the prey with their claws.
Lakelurks are similar to the mirelurk kings of Capital Wasteland, but unlike their cousins, they do not have any form of symbiosis with a mutant crab species.
Strangely, if they follow the player into water, they will have no underwater attacks and only glare at them. But if their sonic attack is fired from land, it will go straight through water as it does through the air, putting the player at a disadvantage of not being able to attack back. It is generally best to pick them off from a distance as they tend to swarm the player if at close range.
Interestingly, their bodies don't float when killed in water, they will sink. However, their guts will sometimes float in water if you make the body "explode" with the Bloody Mess perk, making you able to stand on them and "walk" on the water.
Before attacking lakelurks will roar at the player, giving them a short amount of time to attack the lakelurk without it fighting back.
The standard lakelurk with all characteristics mentioned above.
The lakelurk king is a stronger form of the lakelurk. While visually similar, the king has slightly glowing eyes, fins, claws, and other protrusions. Also of note is the apparent use of body 'paint' on its chest, (suggesting it may have some form of intelligence, or it may be just skin pigment). It can be found in Camp Guardian caves in a large room among multiple lakelurk egg clutches. Killing it will cause the other lakelurks in the cave to frenzy and become hostile towards each other.
The alpha male lakelurk was a subspecies of lakelurk that was to appear in Fallout: New Vegas, but was cut from the game prior to release. It is a stronger form of the lakelurk that is visually identical to the lakelurk king.
Cass mentions that fish are like a lakelurk, but slimier and will not attack you on sight.
Cachino makes a reference to Nero"sleeping with the lakelurks", the post-war equivalent of"sleeping with the fishes", a euphemism implying death coined in older mafia films where someone would have their feet put in cement, then thrown in a body of water, hence 'sleeping with the fishes'.