New Fish All Die

[roxan]

Hi fish lovers

I'd apreciate some advice; every time I try and introduce new fish to my tank within a few days they're dead.

My tank is 190L and has been running for several years. I currently have around a dozen tetras, a rainbow and several angels in there, all of whom are fine.

I've tried adding guppies, these usually go in a few days, and recently I added some rosy barbs, mollies and platys. The platy's are fine (all but 1), but the mollies and barbs all died within a couple of days.

I have a couple of plants in the tank, and also recently switched from a large piece of bogwood to some swamproot.

I'd love any suggestions as to what I'm doing wrong, especially as I believe Mollies/guppies are quite hardy fish to begin with.

On a side note, I curently have gravel in the tank - is this better than using sand for my chosen fish?

Thanks.

 

[200sx]

whats the water stats like also how many of each fish have you got will help to tell us if you over stocked or not

 

[roxan]

not sure on the stats, but i have a dozen cardinals, 5/6 other tetras (harlequin and x-ray), 4 angels, 1 clown loach and 1 rainbow fish.

recently introduced 6 platy, 6 molly, 10 barbs (4 were rosy 6 were another type i cant remember the name).

 

[Duz]

Welcome to the forum, +1 to 200sex comment.

However, (this might not apply) some fish aren't able to be put into certain aquariums for reasons unknown to everyone. I added 6 rummynose tetras about a year ago and within 24hours they had all died, I checked the water and the water stats came back as perfect. So did a 50% water change but sadly they all died. When I went down to the lfs they said that they have 1 tank which can't hold a type of coral even though the water is the excact same as that used in the other tanks. Sounds weird but some tanks can't keep certain fish. Saying that if you are having this problem with multiple species then there is more likely to be a different factor. So water stats and stocking levels might help.

Did you add the 6 mollies, 6 platies and 10 barbs in 1 go?

 

[fluttermoth]

How often and how large are your water changes, OP?

 

[roxan]

Yes, I did add all of the new fish together, and also changed the existing bogwood to swamproot at the same time.

I do an 80% ish water change around every month.

 

[Louiseness]

Just out of interest, how quickly did the new fish die? Are we talking instantly, a couple of weeks...? Did they show any other symptoms (clamped tails, red gills, etc) or did they just turn up dead one morning?

 

[roxan]

I bought them last Thursday, so a week ago, and all but the platy's have gone. By the Saturday morning (so a day 1/2) all but 2 of the barbs had died and most of the mollies, the last molly died yesterday.

I didn't notice anything on the gills particularly. One (and only 1) of the barbs was darting around quite fast, but not jumping out the water. Some of the fish that died had a little bit of white around the edge of their fins.

 

[Louiseness]

Sounds like the first plan of action would be to test your water. I'm suspecting it's a water problem as monthly water changes are a bit infrequent, but until we know the actual parameters (for ammonia, nitrites and nitrates) there's no real way of knowing.

 

[roxan]

I will try and get a testing kit and upload the results.

As it's only the new fish that are dying, could it be that the water is too high in something but the existing fish have an increased tolerance or something along those lines?

 

[Mowbz]

If you have been running the tank without a test kit it seems you could have been incredibly lucky up until now, and adding the new fish has just pushed things "over the edge" in terms of what your tank and baterial colonies can handle.

There are loads of very experienced people on here that will likely be able to diagnose your problem, but they will need your tank dimensions or water volume, a list of its contents (species and numbers) and your water parameters. Get these up ASAP, and someone will sort you out!

All the best

EDIT: My work PC only seems to display half the comments... Seems the problem is already solved

TAXI!.....

 

[Harlequins]

You really do need to get your water tested,by buying a liquid test kit for ammonia/nitrite/nitrate & ph,API is a popular one and available for around £20 on ebay.

Adding all them fish in one go,without checking the stats is a disaster waiting to happen... its more than likely your tank had a mini-cycle spike of ammonia/nitrite and this lead to your fish dying.

Waterchanges need to be done every week preferably,heavily planted tanks can get away with longer in between.

ATM i would do a large w/c to save any other fish possibly being poisoned.

 

[roxan]

Ok I did the tests, results as follows:

Nitrite: 0.1
Nitrate: 10-20
Ammonia 0.6
Ph: 5

Any ideas? I'm guessing it might be to do with the acidity, but not sure how I can change that.

 

[fluttermoth]

Hmm...I think you should do more frequent water changes. Your water is most likely very soft which doesn't buffer against pH crashes (I have the same problem!)

Try doing 25-30% a week rather than the monthly ones.

The ammnonia is a bit of a worry too; it should be zero in a cycled tank. Are you letting chlorinated water get to your filter? Or replacing the media?

 

[roxan]

Ok, but isnt that water a little too acidic for most fish? I read that's why I fail with guppies as they like slightly alkaline.

I am just using tapwater if thats what you mean, not treated. Re replacing the media I dont really mess with the filter other than cleaning it every so often (in fish water).