Camouflage: Many anglerfishes blend in remarkably well with their surroundings. Their dark bodies and sometimes bioluminescent lures make them difficult to spot in the deep, dark ocean.
Bioluminescent Lure: This is their most famous defense mechanism. The lure, which is often a modified fin ray, attracts prey and can also serve as a distraction for predators. The sudden flash of light might startle a predator, giving the anglerfish a chance to escape.
Sharp Teeth: Anglerfishes have sharp, pointed teeth that are excellent for catching prey, but they could also be used to inflict pain on a predator.
Defensive Spines: Some anglerfish species have spines on their bodies that can be used for defense. These spines may be venomous in some cases.
Size and Morphology: Some anglerfish species are relatively large and intimidating, which can deter smaller predators. Their unusual, sometimes grotesque appearances might also be a deterrent.
Deep Sea Habitat: The deep ocean is a challenging environment for most predators, so the anglerfish's habitat itself offers some protection.
Note: While these adaptations offer some defense, anglerfishes are still preyed upon by various predators, including sharks, squid, and other larger fish.
In conclusion, anglerfishes do not actively "protect" themselves in the way some other animals do. Instead, they rely on a combination of camouflage, bioluminescence, sharp teeth, and their challenging habitat to avoid becoming prey.