A scientific cross-section illustration of a rare Opah fish (Lampris guttatus) revealing intricate counter-current heat exchange system, red muscle physiology, uniquely positioned fins, and luminous body surface photophores on aged cream paper, handwritten ichthyological annotations describing each endothermic adaptation, measurement scale in centimeters along the edge, soft filtered ocean daylight from upper left casting delicate shadows, museum archive quality, Pantone-accurate deep ruby red muscle tissues with silver-blue scale iridescence and warm amber photophore glow, composition dynamic to showcase the warm-blooded fish architecture, mood: ichthyological precision capturing the mysterious deep-sea warmth marvel, hyperrealistic details of vascular counter-current textures and fin ray branching visible