Unsure what is happening!

cybanez · Nov 13, 2025

Hi all. I’m new to the hobby. I’ve had my fluval evo 13.5 set up since 8/28. Currently I have a watchman goby and two mini clowns. I’ve also got two red collar snails, three Nassarius snails, and a handful of hermits. I also bought an emerald crab recently.

My water quality has been looking great, weekly water changes, happy critters… but this green stuff is really taking over. I’ve googled it and gotten three different identifications!

Any help with understanding what it is, if I need to change something, etc. would be greatly appreciated!!

Mr. Mojo Rising · Nov 13, 2025

The green rocks are growing micro algae and biofilm, its normal. For the sand, ensure you have adequate water flow across the sand, you can clean it manually or you can get some sand sifters to move the sand for you. But what I see is normal maturing of an aquarium, start getting more algae grazers as the algae grows.

cybanez · Nov 13, 2025

Mr. Mojo Rising said:
The green rocks are growing micro algae and biofilm, its normal. For the sand, ensure you have adequate water flow across the sand, you can clean it manually or you can get some sand sifters to move the sand for you. But what I see is normal maturing of an aquarium, start getting more algae grazers as the algae grows.

Thank you!