All 7 fish in tank died over night. All water tests fine. - Tropical Fish Keeping - Aquarium fish care and resources
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post #1 of 5 Old 03-22-2009, 06:04 PM Thread Starter
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All 7 fish in tank died over night. All water tests fine.

Hi everyone,

1. Size of aquarium 10 gallons
2. Freshwater
3. 2.5 months
4. 3 Red Eye Tetras, 3 Rummy nose Tetras, 1 Clown Pleco
5. No Live Plants
6. Was approx 78 degrees F
7. Tetra Brand filter. Came with tank with Bio Bag
8. No CO2 unit
9. Yes some sunlight through patio window
10. It had been 7 days since the last water change. Changed 25% of the water
11. Once a week
12. Pinch of Nutrafin Max Complete Flake Food. Nutrafin Max Spirulina Algae Tablets for Pleco (just started)
13. Fluorescent deluxe full hood. Approx 10 hours a day.
14. See below.
15. Had the water tested at Pisces Pet Emporium in Calgary, AB. They said all water tests were in normal range.
16. Liquid tests that we have at home
17. Had purchased the Pleco and Rummy noses the previous Friday. They acted normal at the store.

We started our tank in early January. We introduced 3 Red Eyes about a week into the tank's life. Everything was okay for the first couple of weeks. We introduced 2 neon sword tails about 3 weeks later. Both sword tails died after 3 weeks. It turned out to be a nitrogen problem in the tank. As per recommendation we shocked the tank removing 75% of the water and upping Step 2 treatment. This seemed to work and our nitrate and ammonia levels were normal about a week later. We monitored and tested the levels for 2 weeks then decided to try more fish. We bought the Pleco and Rummy noses on a Friday. They seemed to act normal at home and seemed quite healthy. They were eating and their colours were bright. On the following Thuresday morning we woke up to find all of our tetras dead. We immediately removed them and brought them to the fish store. They tested the water levels and said everything seemed normal. They examined the fish and looked healthy aside from the fact they were dead. The Pleco made in until Friday morning and died. We again removed him and took it to the fish store. Same tests, same resaults.

As of today we have removed everything from the tank. Dumped the water. Boiled all the rocks and decor. Replaced the filter, and scrubed down the tank. We have basically started over. Before we introduce new fish we were hoping for some insite as to why all our fish might have died so suddenly.

Thank you for all your help.

Jon and Uli.
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post #2 of 5 Old 03-22-2009, 07:19 PM
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This is something of a puzzle, since everything was (appeared) OK for a period of time and the deaths were sudden. Which leads me to think there was a toxic substance in the tank that may have gradually built up (increased) to the point where the fish could not survive. Normal water tests (I assume the store tested things like pH, hardness, ammonia, nitrite) would not detect toxic substances. And that brings me to the "rock" and decor.

Where did you get the rock? From an aquarium store, or somewhere outside? And what was the decor (wood, ceramic, whatever)?

You can probably see where I'm heading. Something may have leached out from the rock or decor. I had this occur in the mid 1990's from a large piece of wood (bought in an aquarium store no less, but who knows where it really comes from?).

In addition to the above questions, could you also tell us what the pH of the tank was (if you remember), (and what is the pH of your tap water?


Byron Hosking, BMus, MA
Vancouver, BC, Canada

The aquarist is one who must learn the ways of the biologist, the chemist, and the veterinarian. [unknown source]

Something we all need to remember: The fish you've acquired was quite happy not being owned by you, minding its own business. If youíre going to take it under your wing then youíre responsible for it. Every aspect of its life is under your control, from water quality and temperature to swimming space. [Nathan Hill in PFK]
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post #3 of 5 Old 03-28-2009, 08:54 PM
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Another possible source of toxins is aerosol sprays in your house, cleaners,insecticides, air fresheners, etc. Its not always practical, but its best to never spray anything in the same room with an aquarium. If you can smell it near the tank (and maybe if you cant) at least a trace is getting into the water. Never spray glass cleaner directly on the outside of the tank, spray it on your rag away from the aquarium.

You should also get into the habit (if you arent already) of always washing your hand and arm before reaching into the tank. Perfumes, lotions, or other things you came in contact with can be toxic to fish, even in very small amounts.

I think there is a sticky in this forum advising the best ways to cycle a new tank. That may make things go better for you next time.
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post #4 of 5 Old 03-29-2009, 09:26 AM
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hello and welcome.
this should i hope be of some use to you.
if you could let us know if the decore was all from the fish store or not,
that would be a help.
also just to add,have you got any friends with a fresh water fish tank ?
if you have.. ask them if they would donate some filter media from their filter
to help yours.and we can go from there.

when you set up a new tank,hide an extra
sponge or two behind some decor,that way you have
something seeded for you next filter.
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post #5 of 5 Old 03-29-2009, 08:52 PM
IMO there had to be ammonia in the tank. The bio-filter is not going to be suddenly able to cope when you more than double the amount of fish. So ammonia shot up and they all died. The rule for adding new fish is 1/3 of the tanks bioload, so you only should of added 1 fish the same size or smaller as the red eyes. Then waited two weeks before adding another.

I would recommend doing a fishless cycle or a tank clone.

.... I'm probably drunk.

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