My fish are very sick please help!

[Bmenace]

I have a 120L freshwater tropical tank with an Eheim Classic filter & tronic heater: containing 2 peppered corys, 4 otocinclus, 1 bristlenose (I did have 1), & 3 clown loaches (I did have 5).
Water specs: pH 6.5, Hardness 80ppm, ammonia so loe that it didn't register on my test. Temp 26 degrees C
I have lost 1 bristlenose and 2 clown loaches in the past 2 days and am at a loss what to do. The bristlenose appeared to have scraped the skin off its back and its gills were corroded/eaten away. The clown loaches were swimming upside down for around an hour and then lay down upside and were breathing very rapidly and then died within an hour of each other, both appeared to have the same gill problem as the bristlenose. The second clown loach had what appeared to be a white thread about 5mm long attached just behind its eye which dissappear once we took the dead fish out of the tank. When the bristlenose died the local aquarium shop gave us a broad spectrum antibiotic to put in the water but we lost 2 loaches this morning. Any suggestions as to what this may be or what we can do to save the rest of them?

 

[OrionGirl]

How long has the tank been established? How long have the fish been in the tank? Gills problems are often either related to water quality issues, or parasites.

 

[Bmenace]

Nitrite may be the problem

It has been established for around 2 months. We got the aquarium shop to test our water again last night and discovered we had very high nitrite levels - so I think that is where our problem might be. We are going to put active carbon in the filter and do small water changes every day for a week to try and bring the levels down again. The rest of our little guys are cruising along happily at the moment so fingers crossed that this fixes the problem. If you have any suggestions on how to drop nitrite that would be great. Thankyou for your help.

 

[Nuriel]

i suggest BIG water changes (50%) every other day to lower nitrites....sounds like gill burn...are the others doing better now?

 

[PumaWard]

Add table salt at 1tbsp/10g as it will help relieve the effects of nitrite. The activated carbon won't do you much good, so I personally wouldn't bother.. water changes, salt, and patience should do most of the work.

 

[cloud]

Deffinately BIG water changes. The more fresh (dechlorinated) water you can get into that tank the better. Some people say you can over do water changes, but I think everyone on this site will agree that that's a misconception (especially when your water is bad). Fish love freshwater and a bit of disturbance each day untill this is all sorted out is a tiny price to pay.

 

[Bmenace]

Nitrites down and they are looking happier

I will start doing bigger water changes tonight and I will also add some salt. They are all looking a lot happier and healthier (the clown loaches are definately a lot blacker too) and the nitrite levels are dropping rapidly. None of them appear to have any signs of gill damage like the three we lost did, but if they do is there anything we can use to treat gill burn, apart from increasing water quality. Thank you all so much for your help, it is much appreciated!