(Fixed. Thanks for catching that.)
HP: 60
Atk: Rank 3
Def: Rank 1 (-)
SpA: Rank 3
SpD: Rank 2
Spe: 110 (+)
Energy: 68%
Other: Substitute (8 HP), Light Screen (5 more actions)
HP: 80
Atk: Rank 1
Def: Rank 1
SpA: Rank 1
SpD: Rank 2
Spe: 80
Energy: 87%
Other: None
Action 1
Ixia uses Thunderbolt for 6 energy
Roll a D16 for crit: 6 - no crit
Roll a D100 for paralysis: 43 - no paralysis
Feebas takes (10+3+(3-1)*1.5)*1.5=24 damage
Feebas uses Tackle for 3 energy
Roll a D16 for crit: 15 - no crit
Ixia's substitute takes (5+(1-1)*1.5)=5 damage
Action 2
Ixia uses ThunderPunch for 5 energy
Roll a D16 for crit: 2 - no crit
Roll a D100 for paralysis: 74 - no paralysis
Feebas takes (8+3+(3-1)*1.5)*1.5=21 damage
Feebas has 35 HP remaining so uses Flail for 4 energy
Roll a D16 for crit: 15 - no crit
Ixia's substitute takes (6+(1-1)*1.5)=6 damage
Ixia's substitute is destroyed
Action 3
Ixia uses Thunderbolt for 6 energy
Roll a D16 for crit: 6 - no crit
Roll a D100 for paralysis: 5 - 15% paralysis
Feebas takes (10+3+(3-1)*1.5)*1.5=24 damage
Roll a D100 for paralysis: 53 - no paralysis
Feebas uses Scald for 5 energy
Roll a D16 for crit: 8 - no crit
Roll a D100 for burn: 75 - no burn
Ixia takes (8+3+(1-2)*1.5+2-5)=6.5 damage (round to 7)
HP: 53
Atk: Rank 3
Def: Rank 1 (-)
SpA: Rank 3
SpD: Rank 2
Spe: 110 (+)
Energy: 51%
Other: Light Screen (2 more actions)
HP: 11
Atk: Rank 1
Def: Rank 1
SpA: Rank 1
SpD: Rank 2
Spe: 80
Energy: 75%
Other: None