Saltwater Aquarium Problems

Posted by jared burbank on

Does your tank talk to you?  Mine does to me all the time; you just need to be able to interpret what it is trying to tell you. Just recently, I noticed a problem: all of my Bubblegum Digitatas were retracted, but everything else looked just fine. When you have 1000+ frags, some will be closed whenever you take a look at your tank, but in this case 30 of one specific type of coral had all of their polyps retracted.  All my other Digis were perfectly happy, as well as everything else – but those 30 frags were telling me something was wrong.   


Over my 20-odd years of reefing experience, I’ve learned to be able to discern what my tank is telling me.  And in many cases, I’ve learned this the hard way.  I’ve had bristleworms overrun a tank from over feeding, have had tank crashes due to equipment malfunctions, and even saw all of my sps bleach when I first tried GFO. 


But I eventually learned to read my tank, and tune it just right so it sings.  I’ve seen ugly brown acros turn into gems, just by keeping everything in tune.  And just like that one out-of-tune soprano in choir, you can hear it when something is even slightly off.


I normally don’t test my water daily or even weekly, but I knew it was time to break out the test kits and start testing the water to understand why those Bubblegum Digis were upset.  My most logical guess was that something was a little off with alkalinity, so that was my first test.  To my surprise, it was right in line where I keep it, so I dusted off my nitrate kit, and that too was perfectly fine.  Since I was planning on doing a water change the next day, I decided to move it ahead a day.  In preparation for a water change, I always test the salinity level in the system first, and then start mixing my salt water.  And there it was: my specific gravity was 1.023, while I usually run about 1.025. 


There is nothing wrong with running a reef tank at 1.023, but because this little 2% change in salinity, my Bubblegum Digis were telling me something was off.  How did it get low? 


Pretty simple really: shipping out orders, packaging up coral for customers, and skimming wet.  As saltwater was removed during these things RO water was pumped in via my auto top of system.  Usually I check salinity if I’m doing a number of orders, but this time it just slipped my mind.  Fortunately for me, my tank told me before it may have become an issue.  I brought the specific gravity level back up to 1.024, and the Digis opened right back up.  During my next-day water change, I brought it back up to 1.025. 


The key to any fabulous reef system is consistency.  I would have likely been perfectly fine running my system at 1.023 and the Digis would have likely opened back up after a few days of getting used to the lower salinity. But they were closed because something had changed. 


In most systems consistency is fairly easy.  In a system like ours where we’re shipping out coral and getting new coral in all the time, things like Alk/Calc consumption much be watched closely, and tested for frequently.  Other tests I only do when I suspect that we might have an issue, and that is where reading your tank comes in handy. 


The key to reading your tank is in first knowing your tank, inside and out.  You need to know what is and isn’t typical behavior of your fish and coral, so you’ll know when they are talking to you.  I’m in my tanks daily, so know how all the coral should look, and how all the fish should act.  If my clowns don’t come running up to the glass when I walk over, expecting to get fed, maybe something’s up, but then again maybe not.  If my duncans haven’t opened up for 2 days, I know for sure something’s up. 




Learning to read your own tank


  • Zoas/Palys not opening – check for pests, Zoa eating nudibranches, Zoa Spiders, or sundial snails. Check for irritants such as astrea starfish crawling over them, or vermetid snail webs brushing up against them.  And of course check water conditions, ammonia, nitrates, and nitrites.
  • Zoas/Palys covered with white slime – damage or poor water conditions causing bacterial infection.
  • Acros browning out – insufficient lightening, high nitrates.
  • Acros bleaching – too much light for the acro, too low of nitrates.
  • Rapid & Slow Tissue Necrosis – thought to be an infection or bacterial, often brought on by inconsistency in temperature, or Alk/Calc.
  • Light spots on Acros (especially around the base) – Acro eating flatworms, or redbugs.
  • Brown Jelly on LPS – bacterial infection often brought on by damage to the coral such as in shipping, being stung by another coral, or poor water conditions.
  • White spots appearing on Montipora – Monti eating Nudibranches, or being stung by another coral.
  • Fish rubbing up against rockwork – Flukes or Ich.
  • Fish breathing heavy – ammonia, nitrates, nitrites, or being harassed by other fish in system.
  • Fish acting erratic or jumping – stray voltage in tank or being harassed.
  • Fish pits around eyes and head – Marine Head & Lateral Line Erosion, especially susceptible to tangs; poor water quality and activated carbon dust.
  • Swelling of the eye – Popeye, a bacterial infection caused by injury or high ammonia.


These are just a number of problems you can have in your coral and fish – but just  as in my case, if something doesn’t look right, test, and more often than not it’s water quality related.  Always remember if you make a change to your system, do it slowly – and that consistency is the key to thriving reef aquarium.