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dragoonwoman
07-26-2010, 03:38 PM
I have a 6g tank that has been "cursed" - everything I stock it with dies. Sometimes it's only a few days, sometimes it's a few weeks, but in the end all my fish and/or inverts die.

I simply cannot understand why. I have 2 other tanks that get the same schedule of water change and fertilizers as the 6, and those tanks are stable, with healthy, colorful fish and lush, growing plants. The plants in the 6 seem fine; they are putting out new leaves at a goodly rate and showing no signs of disease or deficiency.

The substrate is a combination of Eco-C and pea gravel. The filter contains ceramic beads for BB, and a filter pad for mechanical removal of debris. I am careful to RINSE the filter media in tank water to preserve the BB colony. My well water has no chlorine in it, but I still use Tap Water Conditioner before adding it to any of the tanks. The tank was brand new, and the hood completely closes the top so it's doubtful anything is getting inside.

The heater is unplugged for the summer, so that's not an issue. The light is on a timer, and I'm using a 13w cfl bulb which keeps my plants happy. I feed once a day in a small amount to avoid polluting the tank. Water changes are done weekly, along with the other 2 tanks (see sig).

What could be going wrong? I've torn down, cleaned and reset the tank TWICE now, rebulding the BB with fishless cycling, but as soon as I add stock I start seeing problems. At the first sign of trouble, I do a 50% water change, sometimes daily until all the tests are correct (ammo 0, nitrites 0, nitrates below 20, pH around 6.6). Everything goes smoothly for a short while, then BANG! A tankful of dead fish.

Anybody have any ideas??? I am at my wits end!! :helpsos: :banghead:

Scrup
07-26-2010, 04:02 PM
Have you tried the tank empty with just a filter/heater? Are they getting oxygen through the lid (Its not air tight right?).

Is there a chance you have some stray voltage in the tank from an appliance (filter most likely as the heater is removed)?

Also, with the heater off, the tanks are not getting a big temp flux at night are they?

troy
07-26-2010, 04:15 PM
There could a contaminant in the tank killing them.

Scrup
07-26-2010, 05:52 PM
Also...what is the livestock? have you been trying to same fish or different species?

Sursion
07-26-2010, 05:57 PM
What have you been putting in it? Not a lot can go into a 6g.

dragoonwoman
07-26-2010, 07:49 PM
1) No, the lid is not air tight, it just covers the entire top of the tank.

2) Livestock has been tetras, bettas, cories, snails, shrimp - NOT all together, but separately. 15 RCS OR 7 glowlight tetras OR 1 betta and a snail, OR 7 silvertip tetras. Cories were 3 in with the glowlights (last go-round). I realize that 6g is very limiting on stock, which is why I tried to stick with small fish or inverts.

3) No, haven't tried it with just the filter. I don't know about stray voltage, but I think I would have felt it when I put my hand into the water.

4) Right now it's summer here in CT, so the tank stays plenty warm at night. Our lows have been mid 70's for the last month. When it dips to the 60's I'll plug the heater back in.

5) A contaminant is possible, but I can't figure out WHAT or WHERE FROM. I'm always careful about washing my hands before dipping into any tank, and I double-rinse my hands, too. I have separate EVERYTHING for my tanks - buckets, towels, tools, etc. - so I think I can eliminate those as a source. Everything I use is kept together in a closet so they aren't used for anything but the tanks, and everything is used for ALL my tanks, so if any equipment was contaminated, I would see the effect in all 3 tanks, not just the same one all the time.

BIO-Linist
07-27-2010, 03:57 AM
After the animals died, the plants continued to thrive? This makes me think it is probably a heavy metal because animals may be more sensitive - to plants its just fertilizer. And it would leach more as pH lowers below 7. (You said your pH was 6.6)

What is the tank made of?

Main suspects are substrate and tank material.
In order:
1. contaminated substrate (perhaps containing some metal ore) - either the eco-complete or pea gravel. If you used the same bag of either one in a different tank with no harm, then that component may be eliminated as a suspect - except: However, it could just be one or a few pieces of ore that happened to go in the 6. Substrate has greatest water contact area.

2. contaminated glass (perhaps heavy metal - like copper) Tank glass has a lot of water contact area but nowhere near that of substrate.

3. contaminated silicone (perhaps silicone containing mold inhibitor was used) - this is least likely except in a small tank, because silicone/water contact area is a relatively small. Plants may be harmed.

Tigerfishy
07-27-2010, 09:44 AM
I had a 10G like that once, it killed all my fish. I returned the tank, got my money back and bought a bigger tank lol!!

Australian natives
07-27-2010, 12:21 PM
are the fish just dying? or are they showing signs of illness before death? maybe ur just really unlucky and u keep getting sick fish. =P.

dragoonwoman
07-27-2010, 01:47 PM
The fish will live for a while, and they look healthy, colorful and active. They will be eating well and all that, then suddenly they die. They have come from at least 4 different stores scattered around the state, so I don't think I'm getting sick stock every time.

The pea gravel substrate has been used in both my other tanks, so I think that eliminates it from the list of suspects. My sister has it in her tank too, and she has no problems at all.

The plants are fine - healthy and growing with no sign of disease.

I bought a copper test kit after the 3rd time my shrimp died because I thought there might be copper leaching from the pipes in my 240-year-old house. Test came back zero - not even a trace. One more item off the list.

The only suspect I have is the wood. It's a piece I picked up from our yard when we were clearing the land for pasture. I soaked it for 2 weeks, boiled it for 4 hours, then soaked it for another 2 weeks before putting it in the tank. I'm not sure what the wood actually is, but there's an Anubias plant tucked into a crack in the wood that's growing like mad. I would have thought being in close contact with a toxic wood would have harmed it. Maybe not?

I love the way the wood looks, which is why I used it, but if it's leaching something into the water that's killing my stock, out it goes. I'll look for another piece at the lfs. The Anubias is going to be upset at being moved, but so be it....

BIO-Linist
07-27-2010, 07:12 PM
You didn't eliminate the eco-c

BIO-Linist
07-28-2010, 06:16 AM
(continued)

The plants are fine - healthy and growing with no sign of disease.
Many toxins affect animals but not plants.


I bought a copper test kit after the 3rd time my shrimp died because I thought there might be copper leaching from the pipes in my 240-year-old house. Test came back zero - not even a trace. One more item off the list.
Could be a different contaminant in the glass. Wait, did you test the tank or the tap water?


The only suspect I have is the wood. It's a piece I picked up from our yard when we were clearing the land for pasture. I soaked it for 2 weeks, boiled it for 4 hours, then soaked it for another 2 weeks before putting it in the tank. I'm not sure what the wood actually is, but there's an Anubias plant tucked into a crack in the wood that's growing like mad. I would have thought being in close contact with a toxic wood would have harmed it. Maybe not?

I love the way the wood looks, which is why I used it, but if it's leaching something into the water that's killing my stock, out it goes. I'll look for another piece at the lfs. The Anubias is going to be upset at being moved, but so be it....
Probably this. The wood could be from a poisonous tree.

Lady Hobbs
07-28-2010, 09:26 AM
Very strange. I'd be tempted to give up on that tank myself but there's something going on you just haven't found yet. You've had some good leads here, tho. My only thought was could this tank be in a room that has one of those automatic air fresheners that spray? Or any other sprays that are put into the air like hair sprays, etc?

Hard for me to figure the wood on this one but since it come from the lawn could be fertilizers or weed killers was on it. I'm just groping here and haven't a clue because you're doing everything right. Are you sure that filter is oxygenating the tank enough?

dragoonwoman
07-29-2010, 06:22 PM
I picked up some new wood from the lfs and the root I found in the yard will be removed. It's the only "unknown" in the tank - I use Eco-C in my other tanks, just like the gravel, and the other tanks are fine.

The filter is not the best, because it's built into the hood rather than being a separate HOB or similar. I do run an airstone at night, so there's plenty of gas exchange that way. I figure the live plants give off enough oxygen during the day that the fish should be okay.

I'm going to completely tear down the tank this weekend - take EVERYTHING out, clean it, then redecorate with the new wood and old plants. I'll have to recycle the tank, but I've done that a few times already so it should be easy. I'll take the current creamic beads out of the filter and put them into my Rena on my 46g to get a really good load of BB, which should give me a near "instant" cycle.

Once that's all done, I'll think about adding some fish and maybe a snail or two. OTHER THAN NEONS, what would you choose for stock? No, I don't have anything against Neons, it's just I have a big school of them in the 46g already, and I don't want all my tanks to look alike.