Who Gives A Fish Forums

I'd check the parents' lineage. Some strains are just slower growers. Also, how old are the fry? First two weeks are critical.

My tank's similar to yours, polar. Fry grew slow until I added more plants. Floating ones like frogbit helped shade 'em. Maybe try that?

Water hardness is secondary to consistency. Fluctuations stress fry more than a stable high GH. Ensure your RO mix is identical every time. Use a TDS meter for precision.

Anyone tried adding almond leaves? They soften water and give fry hiding spots. Cheap fix if you're tight on RO.

I'm new to Discus, but my fry tank's at 6 dGH. They're eating fine but not growing fast. Maybe it's normal?