Who Gives A Fish Forums

Another thing to consider is temperature. Monte Carlo prefers it around 72–78°F. Too cold or hot can stunt growth.

Yep, temp matters. My tank was at 80°F and the Monte Carlo melted. Dropped it to 75°F and it bounced back.

If you're still struggling, try dry starting. Plant the Monte Carlo emersed, keep it humid, and let it establish before flooding. Works like a charm.