Hammerhead Coral Questions

[Zenoah1439]

Hello Kevin,

I recently purchased a hammerhead coral from your store and had a few questions.

1. At night, it seems like the coral polyps "retract" quite a bit. Is this normal or should i be giving it more/less light during the day. Is it a sign of some other problem?
2. I had a Lawnmower Blennie that seemed to be getting pretty close to the coral over the past few days. When I got home from work today, my Blennie's color had turned white and he was breathing pretty hard. I isolated him to see if his condition would improve, but he died about 15 minutes ago. Is it possible that the Hammerhead may have "stung" the fish? I've read that they can sting occasionally, but don't know if a sting would be enough to kill a fish. The Blennie was pretty young and small. My other fish (Coral Beauty) and shrimp seem to be fine and are showing no signs of distress.

After I saw the Blennie, I immediately checked temp, chems, and salt int he tank. Everything testing perfect so unless there's some un-tested element I'm missing. Chemicals I can currently test for are Ammonia, Nitrate, Nitrite, Hardness, Alkalinity, and pH. I really didn't want to loose the Blennie, but now I want to make sure there's nothing "off" in the water that will adversely affect the coral (or fish) in the days to come. Is there another test I should be running on the water to ensure there's not something in it that will begin to affect the coral?

The corals in the tank appear to be doing fine. The sps coral (Orange "tree" i bought from you a few weeks back) has its polyps out and looks to be in good color and health, the clam seems.....clammy (i'm not sure what exactly would show good vs. poor health in a clam?), and the Hammerhead seems to be growing, but does retract some nights (as described above).

Current setup is 40g breeder display, 29g sump w/ 12 gallon refugium. I have Macro Algae, Protein skimmer, 750 gph fan and the return line from the sump is running an additional 500-600 gph to the display. Lighting is 2 actinic t5ho and 2 10k t5ho.

 

[kevinpo]

Hello,
Thank you for your detailed post. Most LPS (large polyp stony) corals retract at night. This is perfectly normal. They do not retract for long periods during the day unless something is irritating it. Most fish avoid contact with stinging corals but sometimes do get stung. It usually appears as a white spot from Hammer corals and other corals of the genus Euphyllia (Torch, Frogspawn, etc.). It can be fatal to small fish but it varies from fish to fish and coral to coral (two Hammer corals can have widely varying potency).

Regards,
Kevin