So look for fish that have proper conformation a torpedo-shaped body that glides through the water. The head should be rounded with the eyes proportionally set apart. A fat fish can be the sign of poor nutrition or health. The fins should be erect and fan-like, not torn, bent or closed. And don't disregard the long-finned or butterfly koi that are becoming popular.
Colour counts, too Solid black, platinum and multi tones are just a few of the colours available.
Solids should be rich and glowing. The different colours must be separated with no faded sides or washed-together look. And, remember that fish lose their colour when they are scared. Try to keep your eye on a fish for a short time before having it netted out. Once the fish is in the bag, inspect it even more carefully.