Swimming...A Great Engineering Feat!!

It is so common nowaday to hear hobbyists exclaiming that the ranchu is "A Great Engineering Feat" and I fully agree. Ranchu is "man made"... where over the 100 odd years, the dorsal fin is genetically bred out of the fish. The main purpose of the dorsal fin is to stabilize the fish against rolling and to assist in sudden turns. Against this "no dorsal fin" backdrop, to really appreciate and understand how a ranchu managed to keep its balance and yet abled to swim gracefully and with much power and vigour, like to share how I look into the mechanics behind the swimming.

I reckon one way...very simple and very basic way to understand how a ranchu swim.....is to visualize ranchu swimming as one where one ride a bicycle without a handlebar.

If we ride a bicycle without a handlebar, we must change the whole concept of delivery ....where the grip of power lies and how using those muscles in the legs and lower body, one try to steer the bicycle forward and meanwhile maintain balance without falling over. In a nutshell imagining riding a bicycle without handlebar is as close to what I can as a human try to comprehend and feel how a ranchu swim "without a dorsal fin"...my apology if I sound too animalistic.
 

 

Keeping in mind how one ride a bicycle without a handle bar, we can try visualizing ranchu swimming(without a dorsal fin)...where the concertration of energy/power lies in order to propel the fish forward with much grace and power. Similarly to how one ride a bicycle without a handlebar, the iniation of the ranchu swimming movement begin from the back of the ranchu, gathering power and transmitting through the peduncle and finally spreading out onto the tail. That is why(IMHO) we always emphasize ranchu must have a strong back, good body girth and a good sized peduncle and if the ranchu have the desired proportion/balance and coupled with a good tail with the correct setting...lo and behold we have a "great engineering feat" swimming in front of our eyes.

Below is a video of Japanese Master Chihiro Kudou and his fishes...I enjoy watching the developement of his ranchu swimming.....