Help - Fish Suddenly Die - 2 Year Old Established Tank

[Marclau]

I have an established tank of just over 2 years..........and only lost 2 fish in that time.
Now suddenly, 7 fish have died in the past fortnight.
1 x Gourami, 2x Swordtails, 2 neons, and or 2 others........

Nitrate and Nitrite are perfect 0, PH 7.0, Ammonia 0 but water a little hardness to which i have added bic sod..........

2 x Clown Loaches , 3 x Bristlenoses seems fine, 1 Swordtail etc and all other fish seems fine .........in fact Bristlenose breeding like there is no tomorrow..... 20 Neons.........

I have done 2 30% water changes weekly but today lost my big Gourami.........

Any advice would be fantastic.........

 

[WILDER]

How many gallons is the tank.
Any signs of flicking and rubbing.
Any fish darting around the tank.
Any excess mucas on the gills or body.
Do fish look darker or paler in colour.
Any fish look skinny or bloated.
What does it look like when the fish to the toilet.
Any red streaking on fins or body of fish.
Do the clown loaches look thin.
The neons is there red stripe still vibrant.

 

[Marclau]

Sorry, this was part of my signature..........

O'K, 59 Gallon tank, and no flicking, rubbing or anything at all, nice an d quiet community tank...........Loaches look very good, Neons and nice and colourful...........I can see that they do seem lethargic (Loaches) and together in the bottom of tank and not as active as normal........

I will try 30% water change today and really vacuum bottom and add more plants. Might also add shrimp to clean out tank even though it looks fairly clean.

Ummmmm, thankfully no death in 24hrs.........

 

[WILDER]

Sorry never saw sig.

Signs of a bacterial infection with no symtoms are.
Being pale or darker in colour.
Being listless and lethagic.
Resting on the bottom to oneside.
Fish unable to get off bottom of tank, just sinking back down.

 

[Marclau]

O'K it's no bacterial then as Gourami and sharks swimming freely.

I have done a 30-40% water change again and added 8 new plants........also took out large ship which looked slimmy and had heaps of moss.......cleaned canister filter as well as small reserve filter just in case.
Spoke with LFS and they did not believe it was bacterial either........

Cause all this started happening when i added 20 new Neons and a shark, it may have been a few Neons that were not 100%.
To give the fish a chance to settle, he recommended 3 tablets of antibiotics (low dose) to settle them down enough for the rest of the fish to build up immune.

Now, my LFS has been in the industry 30 years I have never had a problem at all with any fish purchased from there in the past.
He also talked me out of buying any fish until the tank settles..........will now wait and see what happens.....ummmmmmmm

 

[WILDER]

Antibiotics are a bacterial med, Also they wipe all the beneifcal bacteria out in the filter.
You can boost the immune system without using antibiotics, like soaking there food in garlic juice.

 

[lou 123]

I didnt read the responses, are you sure your heater didnt break and have a heat spike?

 

[Marclau]

No, i dont think it a heat spike or anything..........will look for garlic juice........thanks about the antibiotics......

 

[Marclau]

Update, no more death and tank seems to have steadied somewhat............i am now suspecting that it may have been either:
*the plantfood which come to think about it, the deaths happen the very next day
*new fish, it was the same day that i got the sharks and Neons
* 9 new plants.........ummmm, could be anything really..........important lesson is to keep up the water changes as frequently as possible.

In my case, it was 3 changes at 30% each time over a fortnight period..............I'll keep everyone updated should things occur to go downhill.....

 

[Tsu]

I added 5 x neons and my fish started dying too. Just last week. See my thread on here.

 

[bronzecat]

Nitrate and Nitrite are perfect 0 - 20, PH 7.0, Ammonia 0 but water a little hardness to which i have added bic sod..........

If this is correct, then your nitrItes are not perfect?? If you have nitrItes showing then it was probably this that killed the fish

 

[Marclau]

Sorry, that should read 0 for Nitrite and Nitrate.............have had this reading for over a year.............typo error............

 

[Keithoms]

So youve not tested the tank in over a year?

ohh, i get it *slaps forehead*

 

[Marclau]

Once a year?? No way !!!

No I test the tank monthly..........

 

[pippoodle]

did you not quarentine the fish before adding them to the main tank - this may be a good tip for the future so that you are not adding any infected fish into your main stock
so glad things are going better now