[Rainer]

In the past few hours I've lost half my cardinals and cories. Strangely the dwarf gouramis, shrimp, and snails all seem okay. I suspect one of two things:

- when cleaning, I wiped off a film on the front glass extending just above and below the substrate, raising some silt in the process.

- at some point I may have torn a java fern stem when removing a rock it had grown into.

After the silt and probably after the java fern too, I did a 50+% WC with Prime and added the usual EI dose.

A couple hours later we discovered the disaster, along with a thick, oily sheen on the surface. I immediately added Prime and did a 65% WC. The CO2 is still off although it seemed normal prior to the last WC. The fish seem to be improving.

Thoughts?

 

[mistergreen]

Where did the oily sheen come from? Check to see if your water source is contaminated with chemicals.

 

[auban]

whatever the case is, it sounds like the oxygen levels plummeted.


not sure what caused it, but when you think about it, the fish that could breath from the surface made it and so did the critters that could handle low oxygen levels(snails and shrimp)

if the snails and the shrimp are heading for the surface, you know its an oxygen problem. if not, who knows.

what caused the oxygen levels to plummet is anyone's guess.


i would suggest as much surface agitation as possible.

 

[Rainer]

The snails and shrimp seemed to be going about their business so I'm not sure it's a question of lowered oxygen. What could take the O2 levels that low in only three or four hours?

The replacement water came from the same tap as the second WC. I've seen this sheen on tanks that had suffered die-offs a day or two earlier but these guys were all fine at the first WC.

I have multiple "ridges" of water on the surface from the spray bar jets but they didn't break up that sheen. It took dumping in several buckets full of water to do that.

 

[Jeffww]

Did you have lotion on your hands or arm? Soaps? Perfume? Medication?

 

[Lab_Man]

Did you have lotion on your hands or arm? Soaps? Perfume? Medication?

I was thinking the same thing.

 

[Rainer]

Just lost another one.

No soap, medication, or lotion, etc. I used alcohol rub during that period but it had dried well before immersing again. The tank I worked on just prior to this one is fine.

The intake strainer was clogged with thread algae but not enough to impede the filter.

 

[Rainer]

Speaking of thread algae, I used a brand new toothbrush, fresh from packaging, to remove it. I didn't think to rinse it first but it's supposedly safe for human use without pre-cleaning, so I wouldn't expect any toxicity issue. In any case, I would have thought the shrimp would be affected before any fish but they're all acting normally.

 

[Rainer]

Another cardinal died and a second is looking terminal. That leaves two alive from a school of nine. I've lost three chili rasboras but the others seem okay, along with most of the pygmy cories, who made remarkable recoveries following the last WC.

Snails and shrimp are all business as usual.

WTF?

 

[Lab_Man]

I would suspect something got into your water some how. Where do you get your water? City or country well? What changed?

 

[Rainer]

City tap water, no detectable change between the two WCs four hours apart.

 

[King of Hyrule]

What tests?

 

[Rainer]

I didn't run any tests. I'm using EI fertilizers and Prime which have been in use for weeks, so that shouldn't be an issue, and the first WC would have diluted any excess.

 

[Sanchezdaminguez]

This may be late, but are you able to put the remaining fish and inverts into a temporary tank until you get it figured?

 

[JwDiedrich16]

sorry to hear that it sucks. have you had a drought or large amounts of rain latley

 

[Rainer]

No drought, no flood, at least not yesterday. I didn't move them for fear of stressing them to death after they began to recover. The snails and shrimp are fine and there are too many shrimp to catch anyway.

 

[jeffkrol]

No drought, no flood, at least not yesterday. I didn't move them for fear of stressing them to death after they began to recover. The snails and shrimp are fine and there are too many shrimp to catch anyway.

Any chance you "burped" a bunch of ammonia out of the substrate?? What are you using for it?

Shot in the dark..I know Prime should have helped but.. Did you test for ammonia???

 

[Rainer]

I think you might be on to something there. I didn't see any bubbles then but did notice a large one or two released later from one side I hadn't worked on. I forgot about it and didn't think to test for it later.

 

[Rainer]

Substrate is Eco-Complete.

 

[Grah the great]

Lack of oxygen is unlikely since cories are also air breathers and were among the first to expire from whatever is crashing the tank.