Fish keep dying....please help

[mskurdah]

I'm at a total loss for what to do:

I started a new tank about six weeks ago. I put in cured live rock, waited a week did all my water tests made sure it was all good and then put in some fish.

He died.

Waited another week, did tests, put in another fish.

He died.

Repeated this twice more.

Tried several different types of fish -- including a domino damsel.

They all died at night -- appeared fine in the day. I just pulled the domino out after he was in there only four hours and he's almost dead.

Took my water to a LFS and had them test it to see if my test kits were bad -- water came back "A+" 0 ammonia, 0 nitrate, 0 nitrite, 0 phosphorous, 8.4 Ph. Salinity 1.025.

The temp in the tank is steady at 79.

Here's the REALLY weird part -- all the crabs, snails, corals are fine. Acropora has even had good growth. Zoas are all open.

The LFS guys are at a complete loss.....

Any suggestions? The only thing I can think of to do at this point is drain the entire thing and restart it.

Thanks for any advice.

 

[Sk8r]

Several possibilities: how big a pump do you have, and are all of your lids open? Do you have a lot of algae?

A nighttime death of fishes often means 1) a predator like a mantis [heard any clicking sounds in the rocks?] or gorilla crab or b) and much more common---oxygen deprivation, due to closed lids, not enough flow, or too much green stuff on the main tank day/night cycle. Algae/plants give off C02 and USE oxygen in the dark, the exact opposite of their beneficial effects by day. This can suffocate fishes.

 

[mskurdah]

Thanks for the response ---

I do have a fair amount of hair algae. Could this be the cause? I have chaeto in the refugium, but the light is on 24/7. What do you suggest? Should I scrub it all off? The phosphates are at zero. I should also mention that some mornings all the crabs are as high as they can get in the aquarium -- I'm wondering if this is to try to get more air?
Would an air stone help?



The damsel was in a 'quarantine' holding area w/in the tank, so it couldn't be a predator. The bodies of all the fish were unmutilated and I doubt it's a predator.

 

[AquaReeferMan]

Do you have any powerheads in the tank? What is your turnover ratio at?

 

[mskurdah]

I have a closed loop drilled through the bottom. It's connected to an eheim pump and an eheim canister filter (that has the chaeto and lr rubble). Total gph = about 1100. It's a 30 gallon aquarium.

Thanks,

Matt

 

[Sk8r]

Put your refugium on the opposite cycle as your tank: make it produce oxygen at night, by being lighted while your tank is in darkness, but shut its lights down during the day, giving it a 'night' when you can observe the fish activity---gasping near the surface, etc.. You might also run some phosban. The fact your inverts are ok says no copper, no poison: they go first in that case. I'm betting it's low flow or oxygen deprivation. You haven't mentioned the species of fish you've lost, but certain one that swim in open water like tangs use oxy like crazy, while others that hug the bottom use less. The high-oxy fish go first.
You might get yourself a small lawnmower blenny, at least on a temporary basis: he'll clean your tank up. You say you have a cannister with cheato: this is in light? transparent cannister? I'm confused.

 

[mskurdah]

Thanks -- there's a submersible light drilled into the canister filter so that the chaeto will grow. I'll try the reverse schedule.

What you wrote makes sense -- the only fish that lived long was a signal goby on the bottom.

I've tried small wrasses (canary, fairy, six-line), and damsels. BTW: The damsel lived through the night because I pulled him out. I ran an air stone in the tank last night and the crabs aren't all on the top of the rock (as high as they can get). I think it must be the oxygen depravation.

Thanks.

 

[Sk8r]

If it got even a goby, you may need to add a sump or a bubble chamber like a skimmer to aerate. I take it you don't have ANY lids in the water areas---sump, tank, etc: it needs to breathe. A skimmer is a very good way to aerate: they inject a LOT of air into the water, and a hangon skimmer like a remora would do well for your 30g...you can have it on a closed loop [simply means it takes water from your tank and shoots it back in once treated.] You can often buy used ones, as people upgrade to larger sizes, and given a maxijet 1200 pump [I think] there are no moving parts in a Remora skimmer to ever wear out, just one gasket you can replace, so even an old skimmer can be a good skimmer.

 

[SeaView]

One other idea that may help. If you can direct the flow from the return toward the surface to create aggitation. This will assist in gas exchange. Or add a small powerhead and direct the flow toward the surface.

 

[BrianD]

If I read this correctly, you added fish 1 week after you started the tank, and already have corals in there as well.

I think you need to wait until the tank stabilizes, regardless of your testing levels.

 

[prugs]

Do you have glass lids on the tank? If so take them off!

 

[mskurdah]

Thanks for the feedback everyone -- I changed the rockwork so that there is a LOT more surface agitation than I had before, and I left off the refugium light until tonight when I will turn it on.

If this doesn't work I'll try adding a protein skimmer hob for more air.

 

[petoonia]

Check your thermometer, and make sure it is accurate. A broken thermometer can really mess things up.

I do also agree that you should wait awhile before adding anything. Why take the chance with anymore fish. Give the tank some time to mature.