Fish Losses And Strange Behaviour In A New Tank

[joely]

Hi All

I am new to the whole tropical fish world but am giving it my best shot with mixed results at the moment, I have a fluval duo deep 800 (80x35x45) tank which has been up and running for 5-6 weeks now and my fish seem to have a bit of a problem. At first I started with 8 danios but over the course of a couple of weeks 2 died which I put down to just the new tank settling down. I have now topped up the danios to 10 and added 5 ruby barbs but all the fish seem listless and are hanging around the top of the tank.

On closer inspection it looks like a few of the fish have fin rot and I am awaiting delivery of some aquapet medication (no 8 i think but dont quote me on that) but I know fin rot can also be a sign of stress and I was wondering if anyone had any ideas as to what else it could be, the only other thing I can think of is oxygen levels in the water as I have an internal filter which has a venturi on top but at the moment is closed so providing no aeration (on someone elses advice) the fish dont seem to be gasping for air.

The filter seems to be cycling with ammonia and nitrite under 0.1 mg/l with nitrate at 50-60 ppm (i am told the local water has naturally high nitrate levels)

Any Ideas???

 

[karlp]

Hi Joely

Unfortunately, this sort of thing is normal for a new tank with fish that is establishing the nitrogen cycle (takes 6 weeks). As I guess you're aware, the fluctuations of Ammonia and Nitrite during the first 6 weeks which are toxic to the fish cause numerous fish deaths and weakened fish that survive it frequently suffer with secondary infections like mouth rot / fin rot / white spot / dropsy.

Once your nitrite and ammonia levels are steady at 0, providing you follow regular water changes (e.g, 25% every two weeks) then these sort of problems shouldn't re-occur.

In the mean time, I would suggest a 50% water change, to rule out water quality issues and then treat with the fin rot medications.

50-60ppm Nitrate is high for tropical fish to tolerate as well and could cause problems in the future. Have you tested the tap water to verify that the tap water is to blame ?

it's a shame that many fish shops don't do more to help new tank owners avoid this sort of thing with fishless cycling / seeded filter media etc..

 

[The-Wolf]

for a difinative diagnosis try www.fishdoc.co.uk.
most fish illnesses/disease are caused by poor water quality.
what are your water parameters?

 

[joely]

thanks for that, I have been told that local water is about 25 ppm for nitrate although I will test this evening, any ideas on the best way of getting this down? (either in-tank or prior to filling)

 

[karlp]

If your local water is 25ppm then that is a lot lower than the 60ppm you've got in your tank, so just straight water changes should get it down.

 

[joely]

If your local water is 25ppm then that is a lot lower than the 60ppm you've got in your tank, so just straight water changes should get it down.

very true, I will check the levels tonight. Any ideas on aeration, as I say, I have a venturi but currently do not use it so there is no addition oxygen injection into the tank.

 

[karlp]

You shouldn't need aeration for a tank of that size with what is quite a low stocking level. There should be plenty of oxygen in there, unless your water temperatures are very high.

 

[joely]

You shouldn't need aeration for a tank of that size with what is quite a low stocking level. There should be plenty of oxygen in there, unless your water temperatures are very high.

25 is about right isn't it?

 

[badenmate]

hello

 

[benmate]

cool this post has been going for nearly 3 years