Coral Bleaching 101

[FishWife]

It could just be me, but it seems that some of my acroporas are either losing color on the sides or have white tips on the ends. I had assumed that the latter was new growth... but what about a colony losing color on its sides? Is that a matter for concern? If so, what kinds of things cause that, assuming good water perameters, no overfeeding, and dosing CA daily w/a CA reactor running 24/7? Could it be old bulbs in the light fixture? Or maybe light too strong? We're REAL newbies with coral issues... TIA!

[ctenophore]

It could just be me, but it seems that some of my acroporas are either losing color on the sides or have white tips on the ends. I had assumed that the latter was new growth... but what about a colony losing color on its sides? Is that a matter for concern? If so, what kinds of things cause that, assuming good water perameters, no overfeeding, and dosing CA daily w/a CA reactor running 24/7? Could it be old bulbs in the light fixture? Or maybe light too strong? We're REAL newbies with coral issues... TIA!

 

This is a relatively new tank, correct? It could simply be "new tank syndrome" where various non-testable variables are still swinging too much for certain corals to be happy. Things like different strains of bacteria or microalgae that might feed or irritate corals. My suggestion is more frequent water changes for a while, coupled with increased coral feeding to help make up for any lack of zooxanthellae in the corals. That will serve several purposes: feed the corals directly, help establish microfauna populations, keep any irritating compounds in check via water change. Basically try to make your water as much like a wild reef as possible for a while: very clean and with abundant particulate food. You might also run carbon a little more aggressively to really clean up the water.

 

All this assumes that your reported parameters are indeed "good". What about pH swings from running the Ca reactor 24/7? Do you have that much of an alkalinity demand that this is necessary? It could be possible that either your alkalinity is too high or your pH is very low at night from the Ca reactor effluent.

 

Hope this helps

Justin

[hbh]

HI! Problably not new tank syndrome as the set up rivals many in the club and has 4 large tanks for flow, fill, skimmer and a "snack attack" tank filled with cocapods (sp.?). everything else is growing really well. It be worth the time to go see! Scott has an amazing knowledge and ability to figure things out.

[ErikS]

Could it be old bulbs in the light fixture? Or maybe light too strong?

It's always kind of tough to determine exactly why corals bleach - there are quite a few reasons.

 

You say "new" to corals..............how long have these been in the tank (those that bleached)?

 

Often they bleach when moving from one tank to another (as in when you aquire them) - it's the change in lighting that seems to do it. I've moved them from higher - > lower light and from lower -> higher light = both directions have caused bleaching unless you give them time to adjust (even then if they're not tank raised/adapted it can happen).

 

How old are the bulbs? Generally when the bulbs age you'll find corals browning up, less light = they need more zooanthellae to keep going.

 

Also, be careful when do replace the bulbs - the shock of new lighting can cause bleaching.

 

Confused yet? Sadly, unlike reef chemistry there are few x + y = z solutions when it comes to livestock.

 

A bit more information on the cycle for the ones bleaching might get some better answers (i.e. added on, put on the bottom for X days, moved to Y location....etc).

[Gatortailale]

water temp is something that can cause bleaching and same goes for lights. Need more details on tank temp and calcium, alk & ph. Also type of lighting equipment, photo period, location of corals to powerhead.

[ErikS]

water temp is something that can cause bleaching and same goes for lights. Need more details on tank temp and calcium, alk & ph. Also type of lighting equipment, photo period, location of corals to powerhead.

Which is a really good point - we're in that time when it's warmer than winter & yet too cool to run the AC = often a tank hits a higher max temp...............what's your temp tracking lately?

[Lee Stearns]

I second much of the advice above, generally when one think sof a bleaching event it is genearally associated with ligting first (Some kind of change, new lights, lights did not come on, or slow aging of bulbs)

Craig also noted a swing in alk, calcium, ph and or phos can cause changes.

Temperature I had not thought of until I had a power outage for 24 hours- i kept flow and all else in the tank- but my temperature dropped to about 73 degrees at its lowest point- I normally have it about 80-81.

When the power came back on and temperature, lights and all perameters were back to normal I ended up with pale looking corals for about two weeks.

[hbh]

So to slightly highjack this thread, when you buy a coral from a store, the chances of this occuring are high? If so then how does one minimize this? Additionally, if it does occur how can the bleaching be minimized and how can the coral recover? I have a recently bought big finger leather that after 1 week in my tank has nearly bleached from flourescent yellow to whitish with some polyps still happpily showing. Should it be fragged to save some of it or would this stress it more? Does the type of coral matter in terms of stress? In other words, are all corals about the same or some types handle it better? Does the type of container matter ie. a bag vs. hard container for transporting? Does the length of time getting it home matter? If temp. matters how can one know the stores temp.? How can one minimize the affects? Thanks for taking the time to read and for your response!

Edited April 14, 2008 by hbh

[ErikS]

How to avoid?

 

Place the frag low in the tank & monitor it for at least a week. If it shows signs of stress (bleaching) then move it to a more shaded location..........if that doesn't work move it to a higher light location.

 

Polyps out is a good sign = very likely to "recover"......though that's one of the fun parts of this hobby, corals can & do change their coloration based on lighting.

 

My .02 is that temp is the big enemy for transporting coral, keeping them from getting to cold.........but that's a wide range (they gotta get pretty cold).

 

No worries on the store temp, just acclimate them to use tank - put the bag in the sump & wait 15 - 20 minutes.

 

Too high of a temp can cause bleaching, but that generally when it's long(ish) term....i.e. when in your tank.

[FishWife]

Thanks for all the replies!

 

System: it's not OLD, but it has a lot of features that mature systems have: refugium w/cheato directly feeds the system, large aged rocks with lots of coraline algae that had been in a system for years when acquired used, etc. This system as a whole has been up since Jan. 15 (see tank thread below).

 

We're "new to SPS" in the last year... Never had any before last Oct '07.

 

The bleaching that I'm describing is on the sides that DON'T get light. It's an acropora that is about 5" tall. Here it is from dead level on: side view.

 

Here's a view more from the top (the white blob is a crab that lives in this coral) and looks vibrant.

 

Our lights have been the same since we got the system up and running, but we did move them closer about a month ago... maybe 7" closer. The fixture has 4 250 W halides.

 

This coral sits about 8" down from one. Here's a picture in context.

 

Finally, our temperature HAS been fluctuating about five degrees day to day: hotter at 10PM (c. 80-81 degrees) and more like 76-77 in the early AM when we get up. We dose with CA daily and have a CA reactor running... still and all, it's not up over 375 ppm ever. pH is stable right at 8.0-8.3 or so. Photoperiod is 10 hrs. / day.

 

What is this coral called, anyways?

Edited April 15, 2008 by FishWife

[Gatortailale]

It's hard to tell from your photo of light fixture with lamps on whether you have the glass shields installed. IF NOT - then you may be exposing your corals to UV rays that the glass is designed to shield because DE HQI bulbs do not have built in uv shield glass like mogul lamps. Depending on how recent your photo is, probably not cause since appears other corals are okay.

 

no sign of acro-eating flatworms?

 

Could be bleaching on side/bottom because that area of coral is shaded from growth above.

[scott711]

It could also be lack of flow. In addition to what Craig said about lighting underneath the coral.

Edited April 16, 2008 by scott711

[FishWife]

It's hard to tell from your photo of light fixture with lamps on whether you have the glass shields installed. IF NOT - then you may be exposing your corals to UV rays that the glass is designed to shield because DE HQI bulbs do not have built in uv shield glass like mogul lamps. Depending on how recent your photo is, probably not cause since appears other corals are okay.

 

no sign of acro-eating flatworms?

 

Could be bleaching on side/bottom because that area of coral is shaded from growth above.

 

The lights do have glass over the bulbs when assembled.

 

I sure can't find any flatworms anywhere.

 

I figured it was just that the light only hits the inside/tops. From the TOP down, it's ALL green. Thanks!

Edited April 16, 2008 by FishWife

[FishWife]

OK, so, now it started turning brown. First picture below is a picture under a T-5 array in our frag tank (as opposed to under 250 w 20,000 K halides, as in the upper pictures. Second is a repeat of above; coral is turned about 90 degrees. Any ideas?

 

Edited April 18, 2008 by FishWife

[SteveD]

What are your water params? I had a similar problem with a different type of coral. The base was bleaching out. Since then I've correct a low alk problem and it is recovering.

 

I've also done several small water changes over the last month so that could also be a factor in the recovery. I had overall water quality issues due to neglect and the job from H-E-double hocky sticks. Replacing the job from H-E-double hocky sticks also helped.

 

OK, so, now it started turning brown. First picture below is a picture under a T-5 array in our frag tank (as opposed to under 250 w 20,000 K halides, as in the upper pictures. Second is a repeat of above; coral is turned about 90 degrees. Any ideas?

 

[Gatortailale]

Not sure what bulb spectrum you have on the T-5 frag tank - BUT 20K halides will give off blue spectrum and may inturn make the coral appear more "Green" than it really is. Common for corals to have differenct color under different lamp specturm and why most if not all coral sellers post disclaimer about corals pics shot under X bulb and may not look same in your tank under Y bulb on Z ballast.

 

IF you put it up high in your frag tank under T-5 - you are running risk of bleaching it due to sudden change from 20 halides to T-5. Best to put on bottom of frag tank for week, then slowly each next week raise it up some and make it a month process to get it higher. If the dead area upsets you, you can frag it and start a new piece and hope it doesn't bleach or die any more.

[FishWife]

So: brown does not equal decay? It sure looks decayed to me, comparatively....