This deck is pretty straight-forward - get Gyarados' ripping Dragon Rage's and Bubblebeams as quickly as possible.
Cycle Magikarp and Gyarados' with Old Rods and Super Rods, heal with Gold Berries, shed conditions with Full Heals.
This deck is pretty value-based since a 100hp Stage 1 Evolution that can do 50dmg for 3 energies and 40dmg + 50% Paralysis for 4 Energies is pretty hard to beat in this older meta.
Exp Alls are used to boost your Benched Magikarps as quickly as possible while Cleffas/Mantine/Lapras buys time