hello,there is nothing wrong in this grow.everything looks well prepared and environmental conditions look good too.Keeping them at a constant temp is a nice idea.Its looking green.Only thing you can do is to feed her.Start feeding,increase biobizz grow to 1ml/lt or even if you have it you can use biobiz FISH MIX which is better than biogrow.Even though they might be growing slowly,they are healthy.giving nutrients will make it better.good luck for your first grow.update again soon so we have a closer look.