I wouldn't house suckers with food aggressive fishes especially sunfish.The lake chubsucker (Erimyzon sucetta), River carpsucker
A 75g tank is a squeeze, even for a single sunfish (if it's not one of the smaller species). I wouldn't add anything else, especially not a bullhead. Bullheads are fecal mills. Not to diminish their beauty, because they are fascinating fish, but they produce an absolutely enormous bioload.
They are also quite aggressive. Sunfish are aggressive, of course... but bullheads are, too. I've observed bullheads in the wild beating the hell out of sunfish, and they have been known to terrorize their tankmates to death. To keep these species together, you would likely need a very large tank with lots of hiding places, not to mention sick filtration.
The lake chubsucker (Erimyzon sucetta), River carpsucker
Feeder goldfish. When they get too large, trade to lfs for store credit
I'm not expecting it to eat any poop or anything, just the leftover food that hits the bottom.
OP says he just wants something to eat the left over foods on the bottom. He didn't state that his aim was to control water qualityThe sheer quantity of waste that comets produce would offset any good they do by cleaning up uneaten food.
Goldfish and sunfish makes a great combo.The sheer quantity of waste that comets produce would offset any good they do by cleaning up uneaten food.
I refuse house pumpkinseeds in a 75 because they can get big as bluegill, only more taller than length.I don't think a 75 is small for Lepomis sunfish at all. I wouldn't think twice about keeping 6-8 adult Pumpkinseeds or Longears in one with adequate filtration. Larger Bluegills and Redears on the other hand would be more comfortable in a 100 gallon or larger.
would love to see this pumpkinseed as big as a full grown bluegill.