Omegafish[]
The Omegafish is the first of the animated Titans. It will likely be your first Titan encounter, being the only Titan more common being the Slime Titan.
Note: there is a known bug that can make the omegafish invincible. There is no known fix yet.(Even summoning witherzilla won't kill him if you had this bug)
Description[]
The Omegafish is a gigantic silverfish enlarged 16 times. It's eyes are as black as void blocks, and it's very fuzzy and hairy in appearance. When below 1,600 health, it gains a glowing white hot shield.
When not in physical form, the Omegafish, like all true Titans, takes the form of an amorphous mass of particles called a Titan Spirit. In this form, he attempts to steal the souls of all nearby creatures within 64 blocks.
The Omegafish has slow healing factor, meaning it regenerates its health slowly compared to other titans and is the 4th weakest titan. When below 2000 hp it gains a grey shield and attacks faster than normal.
Gallery[]

the Omegafish is basically a god-level silverfish
Behavior[]

An Omegafish in a state of resting
When they first spawn, the Omegafish is curled up waiting for a player to come near. Until you do go near it, the Omegafish won't move or summon minions. Once you get within 32 blocks, it'll wake up and start it's rampage.
The Omegafish will target enemies with long ranged attacks or melee attacks when close enough. He inflicts massive knockback with most of his attacks, like all Titans. The main one to look out for is his tail swipe, which has the greatest knockback of his attacks. Body Slam has the greatest knockup.
In order to harm the Omegafish, you need to stun it. Fortunately, it's as simple as shooting him with a Harcadium arrow. Once stunned, you can either defeat him which is as simple as hitting it with the ultma blade, or subdue him using a golden apple. A subdued Omegafish becomes a mount which you can use to travel around the world. It's minions still hate you though.

A defeated Omegafish.
Upon defeat, the Omegafish will fall onto his back, squirm a little, then lay still on the ground. He will then begin to shrink, at which point, the silverfish he had possessed will die, and the Titan Spirit will go flying up into the sky, to either come back and stalk the player, or to eat the souls of nearby mobs. He may also leave the area entirely, making it so that you encounter him again.

Silverfish
Omegafish Video (version 1.12.2)[]
Minecraft Titans Mod Author Hangout-The Omegafish