Hi ChinaRyukin,

In my opinion, basically both cement and fibre glass could be used. But using
cement, you are going to have a lot of hard work.
Major differences:
1) For concrete, it has a higher tendency to absorb heat and as Yee Miau's
advise as the water level is 6" only for baby ranchu (kuroko), please do remember to cover them, other wise in the hot afternoon , all your baby ranchu would become "masak" (cooked) already.
2) Cleaning is much simpler as the surface is much finer in fibre glass tank than in concrete tank.
3)If you are going to use concrete tank, make sure that there is a hole where
you could drain the water, otherwise, you are going to have quite a task to clean the aquarium.
3) Water cleaning (100%) over a period of 4~7 days is a must, try to make sure that your aquarium are easily clean (including scrubbing), locate in a good position where you have easy access to water...so on and so forth.

What Yee Miau meant is that you do "NOT"need filtration for your aquarium (this is with the assumption that the water would be changed within 4~7 days pending on the stage of ranchu development). You definitely need to put anti chlorin especially when it is on the baby stage, they are very sensitive to clorin.

I intend to buy the big fibreglass as the baby ranchu would be growing very fast as I believe that in another 3~6 months time, I won't have a big space
to rear them. A big aquarium when the ranchu is bigger would help the fish to swim more and therefore allow it to grow better.

Anyone in KL interested to buy the fibre glass tank (5feet x 4feet x 12inch)? I hope to combine and then put in the order to the guy that Yee Miau has recommended. It cost RM 160/tank plus RM 40 for transportation from Ipoh to KL, then you could self collect from my house. This is cheap compared to the one I asked from local KL fibreglass fabricator and they are charging me RM 680 per one.

We need a combination of 10 tanks to place in the order. I am going to order for 4 tanks for myself. Whoever is interested, please pm me ok.

Regards, Ryan