My fish all suddenly got sick and died

[Schuyler]

I was starting small. 14 gallon tank with 4 guppies and three Ramshorn snails.

The tank has been up for a little over a month and send to be cycled. I never see ammonia when I test and nitrates are consistently low.

I got it from my sister for free and I'm pretty sure it's meant to be a sadly water tank. It's an older biocube 14. It seems to have fairly strong flow and I'm wondering if that added stress to the fish.

It had been two weeks since we lost any fish but then we had a female give birth and promptly die soon after that. We moved the babies we could find to a separate 2.5 that we had before getting the bigger one and they seem to be happy and growing.

After she died I suspected the nitrate levels could be too high so I did a large water change in the evening. The next morning one of the females had white bumps (I think ick?). So we treated the tank with ick off and some aquarium salts. The only thing that seemed to do was stain one of the decorations. We ended up treating three days and it seemed to get a little better. On the fourth day she died.

I did another water change and gravel vac to try and clean up any poop because there was some nitrites showing up.

That was yesterday. Today we had another fish die, one is floating by the filter intake not looking like he's going to make it, and the last female now has spots and isn't looking great.

I'm fully prepared to wake up to two dead fish.

Now my questions:

1) Besides quarantine what else could I have done once they were showing as sick?

2) What should I do with the tank now? I'm going to try again but what should I do to get the tank ready for new fish (probably more guppies once the fry are big enough to fend for themselves)

3) How long do fry take before they are big enough that others won't try to eat them?

 

Any advice would be helpful!

[Scapexghost]

1) The original female probably died from stress or complications from giving birth. The other fish were probably "killed with kindness." The big water change, the salt treatment, the gravel vac, another water change, these are all stressful to the fish.

2) probably should leave the tank empty for a month to let any diseases in the tank die out. Alternatively you can sterilize the tank with salt or bleach. 

3) it depends on the temperature and food supply but a month should be good. 

[Schuyler]

On 9/4/2022 at 10:52 PM, Scapexghost said:

2) probably should leave the tank empty for a month to let any diseases in the tank die out. Alternatively you can sterilize the tank with salt or bleach. 

3) it depends on the temperature and food supply but a month should be good. 

Thanks for the advice. Maybe I'll just wait until the fry are big enough and then get more fish to add to the tank. I don't want to sterilize the tank because I have plants and the snails in there still

[Anjum]

Do you have a test kit or test strips? It's a good idea to test your water periodically so you can see where your parameters are & if they're changing. 

[redfish]

Sorry for your loss.  You tried to do what you could.  It can be hard to identify a single issue with so many variables.  Like @Scapexghostsaid, it was likely a combination of events.  Testing like @Anjum mentioned is really helpful to know what’s happening and how to adjust also.  Sounds like you were testing some already.  Quarantine and treating the symptoms is the best recommendation.  Hopefully others will help with your other questions.