Pandu fish symbol

[chimera]

For over 1000 years the symbol of Pandu kings was a fish, on coins, flags and at Visnu Matsya temple. Visnu as Prthu is shown in a chariot with a fish as the pole between the 2 horses chasing Prithvi. He is explained as "guiding" to salvation and Pandu "guide" of Pandavas battled Paundria who forgot that Matsya saved the world.
Is this the reason for the fish of Pandu?