Never tried to paint one, but here's some interesting info on Warmouth sunfish:
Warmouth is one of those sunfishes that changes coloration according to the type of habitat the species is living in. Generally the coloration is as follows; Black spot on opercular flap; eye reddish with 3-5 reddish to purplish streaks radiating across the eye and operculum; body and upper sides brownish to olivaceous with faint vertical bars; abdomen greenish yellow. Single fins darkly mottled. Breeding male is yellow; eye distinctly red.
They usually live about 3 years, are mature at 1 year, and don't normally grow to more than 6-9 inches in length. Warmouth prefer heavily vegetated habitats with limited flow. Found in waters with muddy substrates, detritus, dense beds of vegetation; these habitats having sources of cover including brushpiles, stumps, cypress knees, discarded tires and barrels. Sometimes found in impoundments, generally in backwater areas with extensive brushpiles or stumps. Occasionally found in somewhat turbid waters; seem to prefer clear water with thick growths of vegetation. They tend to congregate in riffle, run, snag habitats in pools and backwaters. Fish less than about 5" tend to remain in shallow water, usually in some form of dense cover, but larger fish occur more in deep water. Absent from much of the Great Plains, primarily because of lack of suitable backwaters, and other flooded lowland-type habitats.
They are found statewide with the exception of the plains streams in the Texas Panhandle area. Here's a general list of the following drainage units for distribution of Warmouth in the state: Red River, Kiamichi River, Sabine Lake, Galveston Bay, Brazos River, Colorado River, San Antonio Bay, Nueces River.