CR,

If you'll be away for some time, and someone is taking care your baby for you. i reckon to reduce some feeding... say 90% instead of 100% just to ensure safety.

Secondly, about the scale. Since you have drag the water change to 7 days. Means the water towards to 6th and 7th day will not be as good. therefore, it may cause itchiness on the fishes' skin. So, they will rub their body against wall or air stone. Just make sure that the air stone surface is not too rough (I've just changed one piece of mine to plastic one, zero sharp edge, to try out.) and your cement tank surface does not have any sharp edges. I've been using those cheap stuff, RM3.50 for 2" diameter airstone. Easily chip off and has very rough surface. It happens to me too. So, I've been doing airstone hunting lately. If found nice ones, will let everyone know.

On the other hand, with your heavy feeding, The water tend to turn bad easily. Therefore, you have to monitor the changes of water daily and closely.

Note:-

- If see small little bubbles (Many, soap bubble a-like.) sticking on the air tube and tank wall. Means water already going bad and do arrange water change next day.
- Strong smell means water already turn bad, do arrange water change next day. If fish already dull, do immediate water change with 0.5% salt; even if it is evening. Same as water change routine, no feeding the next day and 2nd day starts feednig gently, if eating a fast as before, start pushing again, no worries.
- Reduced appetite, normal on day 5-6. just reduce feeding according to their appetite.
- Green water density too high, reduce feeding.

If above problems happens too frequent, means it is time for bigger tank.

Cheers.

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Japanese Ranchu is another ball game