allonyoav asked in PetsFish · 1 decade ago

What went wrong? Mass die off...?

I'm trying to figure out what went wrong in my tank- overnight I had my two bala sharks and all my golden apple snails die, along with a golden algae eater, though my two albino sailfin plecostomae seem fine. The mollies are also still doing well.

I've checked acidity and the filter has recently (a week ago) had the charcoal in it changed. I do have an algae problem though (despite the heavy presence of algae eaters in the tank- go figure).


OK- some details:

Tank size: 400l

Been up and fine for the last 6 months. And nppe- no new fish in that time- in fact I intorduced the bigger fish to help control the rampant reproduction of the mollies. It worked too...

10 Answers

  • 1 decade ago
    Favorite Answer

    Sorry to hear it...

    No fish eats visable an aquarium only micro algae is munched. Are they getting wood in there diet? they love to grind up wood, its part of there dietary need and it's fun to watch the carpentry.

    Pleco's are a super hardy fish and can take quite a beating as there mass allows them to absorb alot more toxins etc than regular fish.

    Mollies are very hardy aswell...only fish I know that can easliy live a long life in fresh or full saltwater aquarium. explain that?

    From what you said the only thing i can get from it was you changing the carbon.

    Even the best carbon lasts 4 days top in a tank and then it becomes clogged but its starts serving another purpose quite effectively.

    (Black diamond and HBH are top brands)

    It becomes a pretty good biological medium. Bacteria colonies with thrive on it and actually move to it from somewhere else.

    Then you change the carbon thus reducing the colonies drastically. The fish try to deal with it and the weakers one die.

    Combine with the fact you may have cleaned your filter too well helping to reduce the colony in there.

    Not saying you did any of this, just trying to think of what may have gone wrong.

    Carbon could also be a primary source of your algae as cheap carbon just leeches phophates all day long.

    A 15% weekly water change does the excact same thing as carbon.

    Thats why no one uses it anymore.nothing but problems. Carbon was used 40 years ago when people thought changing tank water would devastate the water chemistry. We now know its not true but pet stores are still selling carbon. Good for removing meds.

    Just remove it and double up on bio-media live aquaclear bio-max or the eheim splintered glass. That stuff can't be beat at all..easliy the best in the world. But ceramics work very well.

    So the problem may have started a week ago building up to todays deaths as the daily ammonia production wasn't being eaten.

    So everytime you change the carbon this could be close to happening if you don;t have a good bio -media in your filter?

    Fish live and die by the filter. Only a drastic temp and Ph change can kill outside the filter or a renegade mollie but a CAE would kick its butt so unlikley and nothing can catch a scared bala shark.

    good luck!!!

  • You didn't let us know what size the tank is so I'll assume you don't have too many fish(the rule is one inch of fish per gallon of water-MAX)

    Have you checked your ammonia, nitrate and nitrite levels? Most local stores will check these for free if you don't have the tests. Basically, your fish produce waste(ammonia) and it is then converted to nitrite and then to nitrate. When you initiallyadd fish, this cycle starts and a "good bacteria" develops to perform this cycle. If you start with a bbunch offish, have too many fish, or change lots of water in your tank, there will not be enough bacteria to cycle the waste and those levels can skyrocket, causing massive fish loss. Mollies tend to be pretty hardy, so that may be why they are still around. Plecos also tend to be hardy. There is a great article at and they recommend a product called biospira. Hope this helps!

  • 4 years ago

    Actually no, the Irish famine was not only a economic disaster but a policy disaster. The British rule created policies decades before the famine which took Irish lands away from the Irish land owners and the British moved in and took over their lands.... this was legal because the British government took over the land and basically redistributed it into English hands by an act of law. The crops yielded by the "English" lands were mainly exported and the remaining crops were marketed at unaffordable prices (also, they were not abundant in Ireland because of the amount exported). For many people in the British government this polciy was extremely successful because they actually wanted to kill off the Irish. It would be unfair to say that the entire British parliament shared this philosophy though.... many saw that this was not only inhumane but could seriously ruin the Irish economy for decades (which it did) and subsequently hurt the British economy. I don't see the actions of the 18th and 19th century British government towards Ireland as a capitalist action. The money made was insignificant to the English industry.... This was a political action that was intended as genocide (I know that is a harsh assessment but I stand by that). The money was incidental and I would argue was not profitable and more importantly it was not intended to be. I would also point out that you mantioned that the government forbade certain crops to be sold to the Irish. That is true... So how is that capitalism at work if the government cuts off a segment of the market for political reasons?

  • 1 decade ago

    Not alot of info there to help you but I do know that certain species of fish (ex:puffers) release a toxin into the water that can kill some of its tank mates and sometimes even themselves when they become extremely stressed, not saying that's what your problem is but if all your water checks check out in specs then it could also be adding too many fish too soon. You didn't say how long you had them..if you go adding 5 or 6 creatures into your tank all at one time then chances are they are not going to live long...too much stress and your water quality will go down hill very fast

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  • Tammy
    Lv 5
    1 decade ago

    I have a feeling you have new tank syndrome, how long has your tank been up and running and do you have a test kit that tests PH, Ammonia, Nitrite, and Nitrate? Did you tank get to cycle for a minimum of two weeks? (and usually needs 4)

  • 1 decade ago

    What size is your tank? Did you test your water (ammonia, nitrites, nitrates)?

    There are very specific reasons for a healthy tank to suddenly die and these are:

    -ammonia spike

    -Ph crash

    -electrocution (through faulty equipment)

    -Poisoning from an outside source (like soap or house cleaning products)

    -Damaged biofilter


    We need more details and symptoms to offer any help.

  • 1 decade ago

    not sure why they died. Did you check ammonia, copper, salinity? Take a water sample to your fish store and see if they can test it for you.

    As for why you still have algae with algae eaters. Algae eaters do not actually eat algae when they get bigger than an inch or so. Stick with plecos for actualy algae eating.

  • Anonymous
    1 decade ago

    Did you check for ammonia, nitrite and nitrate? Or maybe a disease? There are a lot of possibilities. How did your fish act before they died?

  • 1 decade ago

    As for the first part of your question, I'm sorry - I don't know what the cause was...was the water cloudy?? Do you have any more info?

    I find that the best critters for eating algae are Oto's (otocinclus sp.) and Amano Shrimp.

    Source(s): Aquarium owner for years...
  • Anonymous
    1 decade ago

    continue with the tests......never buy fish from the place you got them agin too

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