Fish don't survive long in my display

Manfred

New Member
Hi, I wonder if I can get some advices and suggestions. I started running a 210g display to keep saltwater fish only since March 2014 (last year) so my tank has been running for just about a year now. I've been losing fish all along and to this date, I only have about 8 juvenile size fish in my display including mostly a couple of angels, a couple of tangs and some green chromis.

I've been quarantining all my fish for 3-4 weeks in a QT prior to adding them in my display. In some cases, the fish died in my QT during quarantine. In other cases, after the fish survived the QT for 4 weeks, I then added them in my DT, they would do well only for a few weeks eating and all, then died with no clear symptoms i.e. no sign of ich or baterial infection etc.

For example, I added in a regal angel, a majestic angel, and a asfur angel to my display 3 weeks ago (after quarantining them for 4 weeks). They were all eating fine and all. But a few days ago, the asfur stopped eating all of a sudden then on the same night, I saw him facing down the sand and was dead the next morning. Then, in the past couple of days, I noticed my other fish in my dispay have kind of been hiding or hanging on the bottom of my tank. Still don't see any signs of disease.

Just for your info, I am using a protein skimmer, a UV, a sump running ceramic bioballs (with filter floss placed on top) for filtration, a phosban reactor, and I have been changing 20% water of my display every week with RODI water. I also run two vortech mp40 in my display to ensure good water flow. So I would like to think I am doing all necessary to keep the tank healthy. But I haven't been able to keep fish in my display for anything longer than 2 months.

What am I doing wrong? I am getting quite frustrated to see all the fish dying, especially when I've been keeping up with my routines and using all necessary equipment to run my tank. BTW, I do check my PH, ammonia, nitrites, and nitrates on a regular basis and all seemed fine except my nitrate has always been on the high side i.e. 10-15 ppm
But somehow,
 

jay0705

Well-Known Member
Since u have angles living in the tank. There maybe aggression when adding new angles. Same w the tangs. Just bc there small doesn't mean there nice
 

Manfred

New Member
I don't know why my nitrates is on the high side but the turbo snails, hermit crabs, and crab that I am keeping in the DT are all doing well and alive. I am even using a phosban reactor and running a refugium with lights on at night when the lights of my DT is off
 

Manfred

New Member
If it is aggression problem, how come after the Asfur died, I found the majestic and emperor angel are both hanging around the bottom of the tank?
It seems something is apparently bothering them but I don't know what it is, cause I tested the ammonia and it is zero
 

Manfred

New Member
salinity is 1.019. I have been advised to keep a lower salinity to avoid ich. I forgot to mention I have a 10 gallon tank placed underneath my DT to keep RODI water and I am running an autotop off so water in my sump gets replenished with RODI water as it evaporates. No direct sunlight in the room where my DT is located
 

Manfred

New Member
What salinity would you recommend to keep at for a fish only system?
I am only using led lights and have them on only 8 hours of the day.
I'm still trying to figure out why the fish kept dying?
 

Manfred

New Member
Yes I agreed. My PH is 8.3.
My friend has been running his fish only system at 1.016 salinity and he has had his big angels and tangs for over 10 years now
 
You must have few death spots that your powerhead cannot be reach, it does not matter even you change water every week, that is why I ask for the picture. you may need to move some rocks to see where are built up? I would do 1.021, but you have invert, I will say 1.022-1.023,
 

jay0705

Well-Known Member
Low salinity is a touchy subject. Fish can handle it much lower than inverts tho. So reefs need the 1.023-25 range. I know lfs that keep it low for disease reasons like u said. However ich can live at any range higher than hypo. Certain other nasties may not but ich can.
That said, your losing fish in a large tank that should be stable. Do u have tops on the tank?
 

Manfred

New Member
Low salinity is a touchy subject. Fish can handle it much lower than inverts tho. So reefs need the 1.023-25 range. I know lfs that keep it low for disease reasons like u said. However ich can live at any range higher than hypo. Certain other nasties may not but ich can.
That said, your losing fish in a large tank that should be stable. Do u have tops on the tank?
Low salinity is a touchy subject. Fish can handle it much lower than inverts tho. So reefs need the 1.023-25 range. I know lfs that keep it low for disease reasons like u said. However ich can live at any range higher than hypo. Certain other nasties may not but ich can.
That said, your losing fish in a large tank that should be stable. Do u have tops on the tank?
Yes I do have glass top on my display
 

Manfred

New Member
How much is open? Not quite sure of your question? Did you mean if I keep the lid of my glass top open? I normally keep them closed
 

jay0705

Well-Known Member
If the tops are sealed tight you have no gas exchange. This will kill fish. Is the top totally covering the tank w no open area?
 

Manfred

New Member
If the tops are sealed tight you have no gas exchange. This will kill fish. Is the top totally covering the tank w no open area?
Yes my glass top covers the whole tank. I am using overflow as well as two vortech mp40 so flow and gas exchange should be good. Don't most people keep the lid of their glass top closed except for feeding time?
If gas exchange is a problem, why would the fish do well in the DT for up to 2 months?
 

jay0705

Well-Known Member
Water movement isn't the issue. The surface of the water needs to be exposed to air. Basically u want the top of your water to look likes its boiling atleast in part of your tank.
To confirm, your tops cover the whole tank w no open areas in back?
 
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