Oyster hitch-hikers?

9Trees29gal · Feb 19, 2026

Hi, just wanted to share some hitch hikers I haven't seen mentioned often. I started my sump with cured live rock rubble from KP aquatics. It didn't have anything growing on the surface but a little coralline when it arrived. Now, 4 months later, all kinds of fun macro algae and micro-fauna have grown, including at least 6 (and probably more that I can't see) of these little bivalves. They have been growing rapidly (doubled size in about 5 weeks). Judging from appearance, I believe they are oysters unless someone with more knowledge wants to chime in! The white projections are part of the shell similar to a spiny oyster. I also believe they are beneficial filter feeders, so they are welcome to stay :-). (And yes, I am aware of the bubble algae, it's not stressing me out either.)

Tahoe61 · Feb 19, 2026

9Trees29gal said:
Hi, just wanted to share some hitch hikers I haven't seen mentioned often. I started my sump with cured live rock rubble from KP aquatics. It didn't have anything growing on the surface but a little coralline when it arrived. Now, 4 months later, all kinds of fun macro algae and micro-fauna have grown, including at least 6 (and probably more that I can't see) of these little bivalves. They have been growing rapidly (doubled size in about 5 weeks). Judging from appearance, I believe they are oysters unless someone with more knowledge wants to chime in! The white projections are part of the shell similar to a spiny oyster. I also believe they are beneficial filter feeders, so they are welcome to stay :-). (And yes, I am aware of the bubble algae, it's not stressing me out either.)

Awesome hitch hiker, cooler than anything you can buy in a store.