25 gallons is too small for an adult pumpkinseed.
In a bigger tank they can be compatible with a whole range of fish. In my 75, I have 2 Pseeds, 2 Bluegill, a Green and 2 small bullheads. The bullheades will eventually outgrow the tank.
Also, Pseeds can be very different from one another. I used to have a 3rd Pseed, but he attacked everyone and had to be removed. The 2 I have now are pretty docile.