Fish Die Off

[deg40]

I have a 60g with Africans. There are also 3 silver dollars as "dither fish," a pleco and a synodontis.

I woke up this morning and 2 of the silver dollars and 2 of the cichlids were dead. A third african was laying on its side panting. I immediatly tested my water and did a 50% water change. All of the remaining fish (2 africans, 1 silver dollar, the pleco and synodontis) were panting. After about an hour the fish that was laying righted itself and they all seemed to be breathing regularly.

The water parameters tested fine. I checked my heater/temp and it was fine. The filters are running fine. I don't understand what could have done it. I moved the tank a week ago so it got a significant water change then. I saved the substrate, all of the filter media and about 20g of water to maintain the bac levels. Everything looked fine all week. When I fed last night they seemed disinterested but that was the only indication that something was out of the ordinary.

I am at a real loss for what could have happened. Nothing that I can think of that would have effected an entire tank that fast makes sense here. Help please I'm concerned about the remaining fish.

[DaisyTattoo]

The symptoms point to a lack of O2 in the tank, but if the filter was running fine and the temp was normal that wouldn't be the case. The next thing I would suspect would be an ammonia spike, but you said you tested the water and all was fine. This is very strange. I don't know what to tell you, but I hope you don't find yourself in this situation again.

[deg40]

O2 was my first thought also. I do keep my water level pretty high and I have a glass cover so there isn't a lot of gas exchange on the surface. I haven't put my power heads back on the tank after I moved it, but even with just the filters there is still about 600gph. The surviving fish weren't gulping at the surface as I'd expect with low dissolved oxygen.

To me the most likely problems would be lack of dissolved oxygen, contamination or gas supersaturation; but none of them seem to quite add up.

Thanks for the input, I appreciate all help. I just want to figure it out so I can prevent a repeat.

[DaisyTattoo]

Do you keep sand in the tank? If so, how deep is it and how often do you stir it up? If not, and you have gravel, how often do you vaccum it?

[deg40]

I use sand. I normally don't stir it up much. The fish move it around a bit, but it was pretty well impacted before the tank was moved. When it was moved I left the sand in the tank with whatever water I couldn't get out. I stirred it up well then, but it wasn't pulled out or washed.

I was a bit concerned about releasing whatever nastiness had built up in the anaerobic areas. I have heard of marine tanks crashing from disturbing impacted sand but I figured with so much clean water going in anything would dilute out. Obviously that may not have been a fair guess. I would have though any ill effects would be fairly immediate, it has been 7 days exactly since the move. Do you think it would take that long? I can't recall what exactly would be in the sand other than high nitrates.

[DaisyTattoo]

Well, I was seeing if it could have been a gas pocket, but seeing how you stirred up the sand a week earlier, I doubt that would be the case. You really do need to stir it up weekly to ensure you don't get a gas pocket however, unless you have some sort of fish that will do it for you, such as a horseface loach. Ok, well if that wasn't it, I think I am all tapped out for now lol. I will keep an eye out for anything that could possibly cause this sort of issue.

[deg40]

Thanks for the ideas

[Star_Rider]

when you say the readings were fine..what exactly were the readings?

ammonia, nitrites and nitrates
event tho you took case it is possible something toxic was introduced to the tank..

[deg40]

Nitrate was 40 (about what it always is)
Nitrite was 0
Ammonia was .25

It certainly seems like it could be some other toxin, but I can't figure out what it would be.

The tank is full of malaysian drift wood. It was cured when I bought it and it has been in there for about a year. It doesn't even release tannins. I don't know if something could have been buried in the wood that just now is exposed it water.

I fed romaine lettuce last night. I rinsed it in tap water like I always do. I do this fairly often and have never had a problem, but it was a new head of romaine straight from the store.

I moved my marine tank the same day as the cichlids and its fairly likely that not all of the buckets were rinsed between tanks. Salt residue could have transfered but it wouldn't have been much.

Am I missing something? I can't think of anything else that could have gotten into the tank.

[DaisyTattoo]

Woo!!! Ammonia is your culprit there bud! It is deadly in ANY amounts! You need to get that under control. Your nitrates really should be below 20PPM too. You may be having a cycle from taking down the tank. But I would bet money that the ammonia is what killed your fish.

[deg40]

You really think at that level? While obviously ammonia is never ideal I haven't had a problem in my fresh water tanks at that level before. This tank has often had ammonia readings of .5 and below.

[DaisyTattoo]

Some fish are very sensitive to it. I'm telling ya, I've seen it before, just as stated in my first post, O2 first, ammonia second....Ammonia actually burns their gills...

[jm1212]

any ammonia is to much ammoina. if your tank cannot keep it at 0, then your tank either is overstocked or does not ahve adequate filtration.

what is your tank size?

what filter(s) are you running on the tank?

[deg40]

The tank normally runs a bit of ammonia, but if it could have exacerbated the possibly low oxygen level I guess it makes more sense to me.

It is a 60g. I have a Rena Filstar XP4 (450gph) and a HOT Magnum (205gph) running on it now. Before I moved there was also a UV (24 watt @ 85gph), a Penguin 250 (250gph), and 2 powerheads (150 and 300gph). The second bunch weren't on the tank last night. I put the UV back in this morning to help deal with any possible contamination.

As for stocking there were 3 silver dollars ranging from 4-6in, a pleco that is 6in, 1 synodontis eupterus at 5in, 3 africans at around 4 in and 1 african closer to 6 in.

[jm1212]

if it is normally running ammoina, there is a problem. a fully cycled and established tank should have no ammoina. is there any ammoina in your tap water?

[Star_Rider]

ammonia is not a good thing..but that said you have ammonia and ammonium.

ammonium is less harmful to the tank..but is used by the bacteria and or live plants as food.

if you use a water condtioner and have chloramines you may see ammonium as many ammonia tests test for total ammonia(included ammonia and ammonium) however, this should be gone in a day or so.
if you are seeing it after a day or two you may be experiencing a mini spike.

you may have affected the bacteria during the move .

[deg40]

fair enough. Ammonia can be dealt with. Really just wanted to figure out if there was some catastrophic problem that I stumbled into.

Thanks everyone for the input and help