Can't keep new fish alive

[codeinlawrence]

I keep on losing fish aproximately a week to two weeks after I get them. My tank is a reeftank and I have a sailfin tang and a banana wrasse that are both active, fat, and have absolutely no ich on them. However, over the past month I have attempted to introduce (at different times) an anthia, a mandarin goby, a naso tang, and a picasso trigger which have all died. For the first two I figured that they were just hard to keep fish that died due to overstress. The naso tang I could never get to eat due to constant harrasment from my sailfin. The Trigger was eating daily until two days ago when he decided to stop eating and being active. Yesterday he died. None of the fish had shown signs of ich before death. I have a 75 gallon tank with a 25 gallon sump/refugium. All of my corals are rather healthy and i have seen no loss of invertabrates (hermit crabs, brittle stars, and a purple lobster). I change my carbon regularly. Nitrates are undetectable and PH is a little low at 7.8. Could such a small fluctuation in PH be the culprit. If not any suggestions on levels to check or ideas of what might be my problem would be helpful.

 

[Racing1]

low PH could be a culprit. What are your other tank parameters? You should always quarantine new fish. Your naso being harrased by the sailfin is why it died probably. Did not get a chance to settle down. The mandarin probably starved if you do not have enough copepods to sustain it. How old is the tank?

 

[Travis L. Stevens]

What are your water parameters and how are you acclimating them? What do they look like when they die? Is there a chance that there could be some sort of bacterial infection or parasites in your system that your other two aren't catching? There is also a chance that the Sailfin Tang could be harassing the new arrivals.

 

[cristhiam]

Is the PH constant at that? what time of the day did you take that reading? then that could be the problem dropping even more at nights.

 

[RichConley]

What is your salinity. What are you measuring with?

Its almost impossible to naturally get a reef to 7.8 on the pH scale. That makes me think your salinity is really low, and you're not acclimating well enough.

 

[Sk8r]

Those are pretty large fish for that tank, esp. if the tank is new. And what sort of skimmer do you have? If it doesn't produce adequate oxygenation, this could be the underlying culprit.