This topic has appeared on many fish forums and a lot of opinions have been put forth.
Many a times, despite the best effort, water condition and food, the black will slowly fade off to be replaced by goldish/yellowish especially on the underside of the belly. This is a huge disappointment after all the effort put in.
I personally experienced first hand the disappointment of buying a charcoal black ranchu, only for the black to slowly fade away. That is, until recently, where I successfully raise 5 blackies from 2.5 inches (now 4 inches), while still maintaining the charcoal black by following the techniques below (though I must admit that point 3 is a killer and I do occasionally skip changing water for a day or two…tak boleh tahan ohhh ;-))
This is just to share my experiences and techniques that I have learned from the Thais sifu!
1) Bloodline
This is the most important thing. If you get a fish that does not come from a pure black bloodline, no matter what you do, the black will eventually fade off.
Thailand is well known for its black ranchu as the colour pigments are very stable, unlike black ranchus from China. It is very uncommon for Thai black ranchu not to have a full black body.
2) Sun light
Black Ranchu must be exposed to full sun light daily. This is one of the crucial elements on maintaining the blackness.
3) Cleanliness of the tank
If you read most fish forum, green water is always recommended for black ranchu. However, for the Thais, they do not advocate green water. To them, the tank must be spotless. They changed the water in the morning and evening and scrub the tank clean every time.
4) White tank
The Thais also rear black ranchu in a white tank (for most of us, it is an uncommon colour, blue being the most common). Not sure the logic of this, but I personally think white colour is a better reflector, hence with a whote base, the sunlight will be reflected to the underside of the Ranchu’s belly, thus “exposing” the belly to sun light. (I put mine in the light blue plastic tub, and fortunately, until now, the blackness is maintained)
5) Food
The common view is – Weat Germ is always recommended while colour enhancing is always a no no.
I have been feeding my blackie with Saki Hikari Purple, and it does not seem to have any impact on the black. Thus, I think as long as the fish is from a pure black bloodline and there is enough sunlight, food will not be a factor.
Hopes this helps for all the Black Ranchu Hobbyist out there!!!
Wy Ken, 8th May 2009





Posted in Tecnical