My poor hammer coral, looking for suggestions

[Narideth]

Hello all, I've somewhat recently started up a saltwater tank, my first, and it's somewhere between 8-10 months old at this point. About three months ago, I put my first corals in, and that consisted of a duncan, blasto, zoanthid, candycane, GSP, and about a week later, a branching hammer coral, all of them on a frag rack about 6 inches below the surface of the water. Getting med-low flow.

All of them were dipped and I found no evidence of pests etc, and all of them but the hammer are doing well. My duncan, GSP and zoas are all putting out new polyps, and the blasto and candycane are both growing. (Even though one of the blastos was completely picked clean by a peppermint shrimp, it completely regrew both heads from the tiniest scraps of nothing.)

This poor hammer just isn't doing well and I'm not sure why.

It's a 15 gallon tank, current parameters are:
Temp: 80 degrees
Salinity: 0.25
Calcium: 440
PH 8.0
Alk: 10.2
Ammonia: 0
Nitrites: 0
Nitrates: 10 ppm

It gets a 3-5 gallon water change every 1-2 weeks, and I was battling a nitrate problem for a bit that has since settled down within the last month I would say. Current inhabitants are 2 ocellaris clownfish, a fire fish, a couple of different snails, a skunk cleaner shrimp, some blue hermits and the corals. All of these guys look healthy and active.

The Hammer has reduced in size by about a third I'd wager since I put it in. It still opens and closes but a decent amount of the tendrils don't inflate or barely do. Was this caused by my high nitrates or is there something else I should be looking out for? Should I give him time to plump back up before I take any further action since the tank has been otherwise holding steady with the above parameters outside of the nitrates? Here's a couple of pictures to show. You can see the under-inflated polyps but how plump the rest look by comparison. Any suggestions would be helpful, thanks!

 

[Donya]

I doubt the nitrate is the root issue. It may not like the current where it is, or it could be getting physically disturbed, whether from recently being relocated or being bothered by CUC animals. Do the hermits crawl on it or snails push against it frequently?

Also what light fixture? Did you change out bulbs on it recently etc.? Changes in lighting can also cause long sulking periods.

Corals in nanos can also fail to thrive for reasons that have nothing to do with water quality or placement - a lot of it is to do with what they're in with and whether the corals are playing chemical warfare with each other. Hammers are often one of the aggressors in that but not always. In a 15gal, any corals have to be pretty happy with each other to coexist.

 

[Colin_T]

All of them were dipped and I found no evidence of pests etc, and all of them but the hammer are doing well.

What did you dip them in?

You want to drop your water temperature a few degrees. Corals will stress and bleach at temps around 82F so 80F is close to their limit. Try to get it down to 76/77F.

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Do you use natural sea water or make up artificial marine salts?
If you make artificial marine salts, do you make it up 24 hours before using it?
You should so the salts have a chance to dissolve completely. The water and salt should also be aerated during this time.

If you use tap water then dechlorinate it as well.

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How long is the light on for?
Lights can be on for up to 16 hours a day but the fish and corals need 8 hours of darkness.

Do you have a full colour spectrum on during the day or only the blue light?
You want a full colour spectrum for most of the day and maximum intensity. Corals love light and need bright light and a good colour spectrum to do well.

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I would do a huge water change and see if that helps. Most of the time corals don't extend out is if there is a water quality issue. A big water change can usually fix that.

 

[Narideth]

None of the CUC really mess with the hammer. They can't reach the corals on the frag rack and the hammer is distanced a little from the other corals, though that was to protect them from its sweepers, not the other way around.

The light is a 50 watt NICREW Aquarium LED Reef Light - It's suspended about 8-10 inches from the top of the water and the corals are 6 inches beneath the surface. It's at about a third total brightness that the light can pump out in both the blue and white spectrum, and the other corals in the same area are thriving. I don't know exact PAR in my tank but according to what I've read and researched, this light should be more than capable and it's only as old as the tank itself, so.. 8 months?

Light is on at 30% white 30% blue for 8 hrs on a timer - this light is overpowered for this tank so I don't keep it brighter than this while I'm figuring out what makes the corals happy.

I dipped two things - Coral RX and Povidone iodine, and all of the corals I got received the same dipping. I buy salt water from my LFS and I don't know when it's mixed, but I rarely use it right away and aerate/heat it until then while also adjusting the salt/fresh mixture to match my tank's salinity.

To be clear, as shown in the photos, the hammer does open up, and has done so every day after it got done being angry over the dipping, it's just slowly seeming to be losing polyps. I could drop my temps though, if the water is too hot.

If I just can't keep hammers in this tank, I can deal with that but I'm debating if I should wait while this little guy still seems healthy enough to pull through, or pass him on to my LFS so he'll survive. It has been a very slow decline to this point though, if that provides any further information.

Thanks for the quick replies!

 

[Colin_T]

LED lights are fine and don't need the globes replaced and your unit sounds like it is more than capable of doing the job. Does the light unit have any red light, because the algae in the coral needs red and blue light.

I would try increasing the brightness of the light to 50% for a few hours each day and see if it makes any difference.

Are any of the other corals sending out sweeper tentacles at night and attacking it?

I know you said the clean up crew can't get to it but crabs can climb just about anything. Are there any small crabs hiding in the tank that might be climbing up and biting it at night?

 

[Narideth]

The frag rack is one of the kinds that attaches to the glass via magnets, and has no contact with anything else in the tank beyond the glass. The cleaner shrimp gets up there every now and then and pesters the duncans, but after my peppermint shrimp destroyed my blasto (and I returned them to the LFS) I've kept a sharp eye out for the cleaner shrimp getting any bright ideas both with the lights on and off. He just likes to steal the food but the hammer doesn't eat quite like the duncans, so there's nothing for it to get interested in. My snails also sometimes make a pass of the rack, but they don't linger after they've scoured the plugs.

I can definitely increase the % of the lights, and I'll go ahead and do that after they come on today. It does have red lights, as well as green, violet, royal, and uv. The other corals shouldn't be close enough to be sweeping the hammer as they all have especially short sweepers, but I can give it a bit more space on the rack just in case it's getting bothered by proximity. The other corals are all living quite close to each other without negative effects.

Thanks for the suggestions, I'll make some small adjustments today and see how it reacts over the next few weeks.

 

[Donya]

To be clear, as shown in the photos, the hammer does open up, and has done so every day after it got done being angry over the dipping, it's just slowly seeming to be losing polyps. I could drop my temps though, if the water is too hot.

You could try letting it cool a few degrees. If it was used to being kept at say 75F, being at a steady 80 could be a tad bit of stress although again wouldn't be my first suspect. IME many corals are happier in aquariums in the 75-78 range than being at 80+ although it varies between strains. Plenty of people run reefs over 80 for fast coral growth but the higher temperatures can also cause boom-bust patterns of alternating growth and survival issues.

How are the polyps being lost? If it's melting or just slowly withering to nothing, the coral could have an infection that a simple dip can't handle or it could be getting slowly roasted by the other corals. You could try running some activated carbon if you aren't already. If it's an infection though there's not much to be done about it without risking killing the whole coral anyway. If the polyps are coming out whole and floating around the tank before dying, that's called polyp bailout - it's a stress reaction that often can't be stopped once it gets going. Polyp bailout can again be stress but it can also have a distinct physical trigger like the juvenile form of certain vermetid snail species burrowing between the skin and skeleton (if you don't have any adult vermetids in the tank you are very unlikely to have that though; they typically are seen by the slime nets they cast at night from crevices in the rock).

If I just can't keep hammers in this tank, I can deal with that but I'm debating if I should wait while this little guy still seems healthy enough to pull through, or pass him on to my LFS so he'll survive. It has been a very slow decline to this point though, if that provides any further information.

Moving it back to the store or to any other tank could easily kill it from the additional stress.

 

[Donya]

Also by being roasted by the other corals, I don't mean by sweepers - corals secrete things into the water that can kill others that are sensitive. Leather corals are especially bad for that but I have a large Duncan colony that has melted some smaller LPS frags just by being temporarily put in a bucket with them - not touching, no sweepers, etc. just shared water.

 

[Colin_T]

Also by being roasted by the other corals, I don't mean by sweepers - corals secrete things into the water that can kill others that are sensitive. Leather corals are especially bad for that but I have a large Duncan colony that has melted some smaller LPS frags just by being temporarily put in a bucket with them - not touching, no sweepers, etc. just shared water.

chemical wars