Tip for everyone:

Don't get a microbe swarm while on a Mount. Get off to aggro and stay off, the swarm will aggro easier off a Mount, and stay aggrod better. Swimming backwards you'll swim at a similar speed to the microbe swarm. (PC) Use "K" to see where you're going.

Solo player tips:

Step 1. Set dino spawn to 2.0 to find Megachelon and microbe swarms easily. (Also up dino tame speed if you wish)

Step 2. Get full scuba suit, but only use the body piece when you need it as the ocean biome in Genesis GREATLY reduces oxygen consumption underwater.

Step 3. Get night vision goggles to spot microbe swarms very easily. Works best at night.

Step 4. Get an X Basilosaurus.

Step 5. Find a high concentration of Megachelon and then swim down to find a microbe swarm. Bring it back up and use the basilosaurus to defend against sharks, eels, and sabertooth salmon (watch near the microbe swarm around the turtle, they'll spawn nearby the swarm)

Step 6. Start collecting Megachelon to build an army.

More Megachelon Taming & KO Tips