I am devastated

[Sierra]

I posted yesterday about my sick zebra danio in a hospital tank. My 6 glo tetras and 5 glo zebra danios were doing great in the main tank. Parameters were ok. Since I moved some gravel to a hospital tank I wanted to add a new one to the main tank. I washed it and soaked it in Prime before adding. I added 1 small bag to the existing gravel ( on a side) last night. Checked parameters in the morning. All was fine. Fish were doing great. One tetra had a tiny rip in fin. I added 1 cup of Melafix to 20 gal tank. 2 hours laters 2 tetras are dead. One still struggling.
I did an emergency water change. Moved the dead fish to salty solution. One is still nearly breathing.
How to revive the fish??
What caused it? Adding gravel or melafix??
I did Melafix treatment before and all fish tolerated it well.
Please help!!

 

[Sierra]

Anyone?? Please share your thoughts. The 4th fish has just died. What should I do with remaining 2 tetras??

 

[Aiken Drum]

Id move them to the hospital tank

 

[Sierra]

Thank you. I will do that.
Also, I removed newly added gravel as it was just a small addition not mixed with the old gravel . I did 75% water change and added Prime. Danios are doing fine.
I am so upset about my decision to add more gravel. I killed some healthy and beautiful fish. Can’t forgive myself .

 

[Aiken Drum]

Im not really sure what happened, but the most likely thing was stirring up something when you removed gravel. Even if your water parameters showed up good when you started to notice things going wrong it could have have been due to things went array before you managed to test. For instance in a well cycled tank toxic levels of ammonia you may release will cycle out in 15 to 20 minutes but the health issues could last years.

 

[Sierra]

That makes sense.

 

[Aiken Drum]

If you are regularly stirring up the substrate or gravel vacuuming then things won't elevate because it won't have chance to build up. But if its not something you do regularly then it will stir up stuff thats had chance to build up to potentially toxic levels.

Consistency is key to everything.

As said im not really sure what happened, but if your fish are dying in tank #1 and you have the option to move them to tank #2 then i would move them. It will give you time to assess whats going wrong.

 

[Sierra]

I vacuum gravel regularly but not entire floor at one time. I don’t want to clean it too well and cause ammonia spike.
The gavel that I removed was not vacuumed recently as I wanted to move the beneficial bacteria to the hospital tank. Now I know what I did wrong. Thank you

 

[Sierra]

Update:
Hello, 2 days after ammonia exposure. 5 tetras dead, 1 still alive, doing not too bad. Swimming normally, eating, no signs of gasping for air. All danios look ok,
I noticed today that tetras body is turning gray/blackish. Danios look also slightly darker. I take it for a good sign that their bodies are healing. I keep monitoring the parameters and added some stress coat. I am planning to do a 25% WC.
Should I add any medication to prevent bacterial infections? Or just let them heal on their own?
Please advise. Thank you!!

 

[Colin_T]

If they don't have a bacterial infection, don't add medication.

 

[Sierra]

Got it. Thank you

 

[michmich]

One cup of melafix to 20 gallons?! On my bottle, it says you should add 5ml or 1 tsp to each 10 gallons. That would be 2 tsp for 20 gallons, not a whole cup. Was that a typo?

 

[Aiken Drum]

The dosing cap/ cup on melafix holds 10ml, so 1 cup for 20 gallons.

 

[Colin_T]

Whenever you use medications, make sure you work out how much water is in the tank. A lot of aquariums are sold as x amount of gallons but in reality they usually hold less than that. Below is some information about working out water volumes in square or rectangular shaped aquariums, and what to do before you begin treatment.


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Before treating an aquarium with medication, do the following:
Wipe the inside of the glass down with a clean fish sponge. This removes the biofilm on the glass and the biofilm will contain lots of harmful bacteria, fungus, protozoans and various other microscopic life forms.

Do a 75% water change and gravel clean the substrate. The water change and gravel cleaning will reduce the number of disease organisms in the water and provide a cleaner environment for the fish to recover in. It also removes a lot of the gunk and this means any medication can work on treating the fish instead of being wasted killing the pathogens in the gunk.
Make sure any new water is free of chlorine/ chloramine before it is added to the tank.

Clean the filter if it hasn't been done in the last 2 weeks. However, if the filter is less than 6 weeks old, do not clean it. Wash the filter materials/ media in a bucket of tank water and re-use the media. Tip the bucket of dirty water on the garden/ lawn. Cleaning the filter means less gunk and cleaner water with fewer pathogens so the medication will work more effectively on the fish.


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To work out the volume of water in the tank:
measure length x width x height in cm.
divide by 1000.
= volume in litres.

There are 3.785 litres in a US Gallon
There are 4.5 litres in a UK gallon

When you measure the height, measure from the top of the substrate to the top of the water level.

If you have big rocks or driftwood in the tank, remove these before measuring the height of the water level so you get a more accurate water volume.

You can use a permanent marker to draw a line on the tank at the water level and put down how many litres are in the tank at that level.

Increase aeration/ surface turbulence when using salt or medications because they reduce the oxygen level in the water.

Remove carbon from the filter before treating with chemicals or it will adsorb the medication and stop it working. You do not need to remove the carbon if you use salt.