"The Butterfly Tail ... often flutters its lovely tail fins like a girl in the flower of her youth taking a leisurely stroll- all innocence, vitality, and not a hint of worry or sadness. Words simply cannot do it justice."
The dorsal fin should be held upright. The leading ray on the dorsal fin should come up straight, and the following rays should curve slightly backward. The telescopic eyes can be globe eyes, dome eyes, flat eyes, or anything in-between. The fish's body should be deep and round, and some fish have a slight hint of the ryukin-like hump starting behind the head. Traditionally, these fish are meant to be top-view fish (and many would argue the tail is best appreciated this way), but they are gaining popularity as side-view fish as well. The butterfly telescope is found in many different color types including: panda, black, white, purple, lavender, calico, red/white, red, kirin, metallic calico, and sakura. Since more traditional color types like red, red/white, and black have been established for longer, they tend to produce healthier and more robust fish. So for beginners wanting to try butterfly telescopes, it's a good idea to stick to the more traditional color types at first.
I have found these fish very rewarding to keep because they generally have very sweet and laid-back personalities. A few can be feisty, but for the most part, they are docile and can easily be trained to hand-feed.
Common Telescope Eye Types
Top-view Photos of Eye Types
A calico butterfly with globe eyes.