As of last night, Second Fleet took pretty severe losses during the initial stages of the pacification of 40 Eridani.
The order of battle was:
1 Monitor: 14 15cm near-ultraviolet lasers, 8k tonnage total.
2 Patrol Boats: 3 15cm N-UV lasers, 3k tonnage.
2 Destroyer Escorts: 4 triple-mount 10cm N-UV turrets, intended for point blank anti-missile defense. 8k tons
2 Frigates: 30 counter-missile tubes spread across 6 launchers for distance AMD. Also 8k tons.
3 Guided Missile Frigates: Primary Ship Combatant, has 4 launchers spread across 4 fire controls, at size 6. Surprisingly effective as the AI can only fire at one salvo per 5 sec interval, so by having 12 salvos it eats up a lot of anti-missile defense without losing much. You guessed right: 8k tons.
1 Frigate Leader: Sensor Ship + Flag, and surprisingly also 8k tons.
4 Escort Carriers: 2000 hangar space, intended as a stopgap measure until I can get bigger ships originally but it ended up being pretty useful all around since they're cheap, quick, and hard to detect. Finally, these are... 8k tons.
Of those, the FFGs are completely tapped dry on missiles and defenseless, the Flagship was one second there and the next /gone/, one escort carrier bit a salvo of 125 missiles from a wave of FACs, both DE are gone, the Monitor was reduced to a crippled wreck bleeding atmo and corpses, and a patrol boat learned why it's a bad idea to charge a 20k ton particle beam ship when you're effectively unarmored. Even though I've got reinforcements en route, losing a third of the fleet and having my visual range reduced to a fourth of what it was is incredibly painful. I think I've managed to take out their entire fleet, though, but I'm honestly not sure about that. Even if I have, I'm going to have to either destroy their shipyards and rebuild them when I take the territory, or park the incoming pair of monitors on their planet and hope that 168 burst damage will be enough to kill anything that comes out of them while the First Pacification Division is in transit.
Then again when you consider this is the third race I've pacified and incorporated, maybe it was about time for me to get my nose bloody.