Guppies All Died Within A Week - No Symptoms - Fine At Night And Dead In The Morning Question

Discussion in 'Freshwater Fish Disease' started by JaneGael, Jul 12, 2019.

  1. JaneGael

    JaneGaelValued MemberMember

    Well, I shouldn't have put two more guppies in my established tank without quarantine but they were from a trusted source. They looked healthy and were active and eating well. Then, after about two weeks, the original ones started dying. One morning 4 of them were gone and then 3 more, it took a little longer for the rest but I lost my last one this morning. I started with 9 and now have 0. It was such a pretty tank too. :(

    They were active and hungry at supper and seemed normal when I checked them at light's out. But they were dead in the morning. Every one of them died at night. Every one looked completely healthy. I'm wondering if the big nerite in there is a hitman. I've never had fish die like this. I have no idea what to do. I can't pull the 4 ottos and quarantine them as I'm not only out of quarantine tanks, I'm out of flat surfaces to put another one on. Can I just keep putting in a couple of small algae wafters to feed them and the snails and keep it cycled until I can tear it apart?

    I use an API test kit. Ammonia 0, Nitrite 0, Nitrate 4, pH 6.5
  2. Heron

    HeronValued MemberMember

    Guppies do best in harder pH water. PH 6.5 is lower than they really need. Your tank should stay cycled but the bacterial colony sizes will drop with the lower load. When you add more fish you may take a few days get the numbers back up. Ideally add new fish a few at a time. Or you could try to keep the colony sizes up by adding a few drops of ammonia each day but be careful not to add too much as this could cause an amnonia spike which could harm the fish in the tank.
    Guppies tend not to show signs of illness until they are too ill to save so if you have a problem you don't notice symptoms until they start dying. The low pH may have stressed the fish and made them vunerable to disease. Before adding more guppies try raising the KH by adding coral sand into the filter. This should then raise the pH and make it more stable. A stable pH is more important than the correct pH
  3. OP

    JaneGaelValued MemberMember

    Do I dare add more fish without breaking it down and sterilizing everything?
  4. Heron

    HeronValued MemberMember

    If you have somewhere else to house your fish for a few days I would definitely consider cleaning it completely and changing all the water but keep your old filter media alive then it should re cycle quickly. If you haven't any alternative accommodation conduct a series of daily water changes. I would give it a couple of weeks since your last death before adding more fish. Ideally you should quarantine your new fish for 2-3 weeks before adding them to your tank. So by the time your new fish are ready for the main tank the tank should be ready for them. If you clean out the tank I recommend using those tablets you use to sterilize baby bottles. Remember to rinse VERY well.
  5. Zka17

    Zka17Valued MemberMember

    I am struggling to establish a guppy colony too... Started very similar like you - my first 9 guppies died within a week in an established tank (1-2 a day). They were clearly sick. I've started a quarantine tank for the next set of guppies and started to medicate them. Did slow down the dying rate, but ultimately I am going to loose the adults - several females did give birth before dying, and the fry are doing exceptionally well.

    I do know (from previous experience) that guppies are doing poorly in low pH - specifically if suddenly drops. I am wondering when did you measure the pH of 6.5? The CO2 levels are the highest in the morning, right before you turn on the lights (both plants and fish exhale it without light), then as the lights turn on, the plants start using the CO2 (fish continue to produce it) - causing a decrease in levels. CO2 is the major cause of decreasing pH.

    So, if you have measured pH of 6.5 in the afternoon or evening (after the lights were on for a while), then it means that during the night your pH will drop even more.
  6. Heron

    HeronValued MemberMember

    The key to a stable pH is a good KH. KH goes by a number of names but is basically the buffering capacity of the water. In other words a higher kH will stop the pH from dropping until more acid is produced. It is a good idea to use a test kit that has a kH test in it. If you have a kit that doesn't you can by one on its own. for guppies I would recommend a KH of at least 4-5 . In my case this keeps the pH at a stable 7.5 .
    Guppies are sold as Hardy fish but in my experience many die within weeks of purchase regardless how well you keep them. They are bred in huge numbers and often are genetically poor, especially if you get them from the large chain shops. I have a number of tanks with different fish and my guppies give me more problems than the rest put together.
  7. Heron

    HeronValued MemberMember

    I forgot to mention the best way to increase kH is to add crushed coral / coral sand into your filter. Alternatively you can add kH up to you water when you do water changes. Personally I would go the coral route. As with all water parameters changes must be gradual. So add a little coral each day rather than just dumping a load in
  8. OP

    JaneGaelValued MemberMember

    Thank you for all the helpful replies.

    I actually mis-typed the pH and it's 6.8. There is a bag of crushed coral in the HOB. I'm a little surprised that it's that low. Maybe I need to add fresh coral, as this was in another tank before being placed in this one.

    Reading up on guppies dying has been a lot more informative than reading up on how to keep them. Apparently they are so over-bred that they've become extremely fragile and most pet store ones don't even live a year. Since my favorite tank has zebra danios and pepper cories who are nearly four years old, I don't think I'll try guppies again.

    I'm seriously considering ordering some sunset Mickey Mouse platys when the weather cools off. I'll get a half dozen and let them breed, at least for awhile. They will be unusual enough so that I will be able to unload extra babies at my local fish stores. They seem to be a sturdier fish and I always enjoy interacting with them at the pet store.