Arguably, ranchu are the most handled fish I know. With frequent mandatory water changes, they have to be transferred by hand every several days. More so, young ranchu are picked up constantly, almost daily, to evaluate their development and for selection purposes. Often in the videos ranchu are presented in the hands of a keeper to show their outline, fins and overall quality. By the time ranchu matures, it has been held a great deal. My ranchu, for example, are so tame, they don't even try to swim away when I pick them up.
For all ranchu keepers and handlers, I would like to give a few recommendations to assure that your ranchu are minimally stressed when handled.
HANDSHands must be cleaned, but NOT with soap. I wash and rub my hands under warm water for a few minutes before handling the fish. It is good to use a brush to scrape hands under water. NO lotions or hand creams can be used. If I have handled someone else's fish, I sterilize my hands with alcohol and wash them under water before handling my own fish to prevent contamination.
Right before touching ranchu, I dip my hand in the tank with ranchu to chill it. It is especially nessesary when the water temperature is low. Under normal circumstances, my hand's temperature is 90-93F (32-34C) and the fish temperature is about 1 degree higher than that of the water. Holding your hand in the colder water will minimize distress. Imagine a masseur with cold hands giving you a back massage.
Ranchu must be held properly to avoid any damage to the fish body, fins and tail. Their tail must be positioned away from you and their belly must be supported by four fingers cradled together and contouring fish's belly. A thumb placed over the fish's back will secure and prevent it from slipping out. Hold it softly, creating a loose "hand harness" around the fish as in two images below. This handling technique is used when transferring ranchu from one container to another.
When inspecting or showing off your ranchu, softly but firmly hold ranchu between the thumb and four fingers as shown on the picture below, keeping the ranchu submerged.
RANCHUIt is unavoidable to take ranchu out of the water to transfer them during the water change. But, taking ranchu out of the water during check ups or demonstration is unnecessary. After ranchu is in your hand, hold it right under the surface of water, so the fish is submerged (picture above). If topical medication must be applied to the fish's body, I try to keep at least the fish's head in the water. Although ranchu isn't a deep water fish (in which case surfacing would be devastating) the pressure change between being under water and in the open air is stressful and could affect the swim bladder, especially if it is already compromised. At all times avoid or minimize the time when ranchu are kept out of the water.