If you have another smaller tank, it'll be great cos the area will be much smaller there. and you can place it temporary at someplace with longer sunlight duration. Say 32" x 20" size is quite ideal. Something similar size also can. I think you can change over to the small tank anytime if the small tank is available now. you only need it for 3-5 weeks. then they can go back to this big tank already.
The fish looks good to me. Will ask LiewKun (Vincent) to double check.
Next time, you can put an egg (approx 60 gram size) for size comparision (just another common practice in Japan, for your info only.)
By the way, 頑張って下さい means "continue to work hard and strive for best result" I think it is pronounce as " KanBaTeh KoDesSai"... need to confirm with LiewKun.
You can cross check in
www.ranchu.net on their 60 days old fish and compare them to your on development. It looks very very similar.
Cheers,