Red Melon / Marlboro Red
A variant of Discus (Symphysodon aequifasciatus)

Representative Discusphoto — a dedicated image of this exact morph isn't available yet.
A patternless deep orange-red Pigeon-derived strain bred for the most saturated solid red body possible. Among the most demanding to keep in full color.
Keeper tips for this variant
Red is heavily color-fed; sustained color needs astaxanthin/carotenoid-rich foods, but be honest with buyers that hormone- or dye-fed reds fade — a naturally pigmented fish holds color long-term.