Just got latest feedback from Japan. The babies doesn't need to go into full carpet algea diet so soon. Do not recommend to culture carpet algea with other fish in the tank. or can wait till baby ranchu arrive then start to culture. No need hurry on this matter.

On the other hand, you can start culturing carpet algea and continue feeding them with bloodworms after you recieved the fish. till you reckon carpet algea is thick enough, then you can start full carpet algea diet. But not now, I'll give update on when to start. For those who starts late, they can drag the diet longer, it's all flexible. Best is to share pic in the future for comments.

As long as the sunlight is sufficient and tank is not crowded, there'll enough algea for them. Don't worry as long as you setup nicely. Initial 100% clear water , maybe at day 4-6, you'll notice green water appearing. Then back to clear water after 100% water change. Normally, water change at this stage is around 1 week.

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Japanese Ranchu is another ball game