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[CanadianReefer]

Poking around my aquarium at night, I found a few odd creatures. Can anyone provide insight? The one I think may be an asterina starfish, but I understand they are small. I have one that is at least the size of a toonie (it's a Canadian thing) and is frequently found wrapped around one of my sps corals, as shown in the first photo. I wonder if that's why that coral has been struggling lately??

The crab - not sure if he's good or evil - but he's pretty big for a crab.... looks red with orange eyes and a mix of orange and black coloured dots.

Lastly, this algae is something I've never had before. It looks glossy like bubble algae but it is tiny little stick-like patches.

 

[Flippers4pups]

The green algae is a form of bubble algae.

The crab I would trap and remove to the sump.

The coral issues are not definitive. Cant see if its bugs, the crab could be eating it or other stressors at work. The star fish is a asterina. They can eat coral. If you suspect they are, remove them when seen.

 

[cristata.reef]

I have that same algae and it hasn't really done much. It's not an overwhelmingly fast grower but it expands at a decent rate. Mine formed a ball and grows like an epiphyte around some red palm macro. No ID tho sorry