Fish Deaths After New Fish Added

[Wendy-Jane]

Dear all,

Please has anybody got any thoughts/advice on the following? I have a community tank that has been totally stable (no illnesses, no deaths) for all of this year and much of last. If The Wolf is reading this, you may remember me asking your advice about a Pearl Danio who had ripped his operculum off back in October 2007- he's still going strong thanks .

The tank's not entirely fully stocked - haven't added any fish for over a year as everybody has been so happy. The details are as follows:

Tank: 180 litre Juwel

Occupants
2 pearl danios (approx 3 years old)
2 white clouds (approx 3 years old)
8 cardinal tetras (about 2 years old)
3 harlequin tetras (about 2 years old)
6 sunset platies (over a year old)
4 bengali loahed (i think that's what they are, vertical stripes and eat snails - over a year old)

Water stats
pH 7.4
Ammonia 0
Nitrite 0
Nitrate 10

Anyway, last weekend I thought I would get some guppies. I tried keeping guppies several years ago, but they did not do well, and I gave up, but because the tank has been so stable recently, and there's space, I thought I'd have another go. So I got 6 males, and brought them in by floating the bag etc, but within 24 hours two of them had died.

Now that was bad, and I was very upset, but yesterday I got in from work and one of my white clouds had died. Now this old boy was about three years old, and has had a tumour growing on his nose for over a year, so I kind of thought it was just coincidence, but I've got up this morning to find THREE of my cardinals have died overnight As you can imagine, I am distraught. I will never ever put strange fish straight into my tank again, I need to quarantine them, I know that now, but what is going to happen to the rest of my fishes now - what can I do?

I've done a water change this morning and added anti-internal bacteria medication, because there is no sign of anything on anybody and I didn't know what else to do. I'd appreciate any suggestions on what is going on or what to do - have the guppies brought something in with them? Please help. I so don't want to lose any more of my fishy friends

 

[WILDER]

R.I.P.

Happened to me until I bought a quarantine tank.

Do the guppys look skinny or bloated.
Any fish showing signs of laboured breathing, gasping, flicking and rubbing, darting, excess mucas.
Keep a look out for when the fish go to the toilet. New, and original fish.

Signs of bacterial infection is.
Fish will look pale or darker in colour.
Fish will be listless and lethagic.
The fish will lay on the substrate, tiling to oneside.