Not really new, but still novice.

[Holyreeftankaquaman]

I have been on and off saltwater for about 20 years. My most recent tank is about 5 years old, but it was abandoned for about 2 years. Basically all i did was sprinkle some fish flakes in the tank.... i did t really even notice if all the fish were still there. Yesterday i decided to finally clean all the algae off the glass to see what is inside. Had to scrape off all the coraline aglae on the glass.

Here is my setup:
30 gallon tank with led lighting corals and live rock
20 gallon sump with led lighting and macro aglea and live rock
R/O unit that will refill the tank when the float activates the switch.

1 clown is now pretty fat and big
1 blue damsel

1 cleaner shrimp

THings that died while i abandoned the tank
1 peppermint shrimp
1 emerald crap
All the coral except 1, which has taken over the tank and is even in the sump.

My question is, what is this coral? It came from that one white plug u see there. Somehow it moved,multiplied and killed everything else. Its even griwing on the powerheads.

 

[shakacuz]

kenya tree, likely