Now Sure

[DarrenJThomas]

Over the last couple of weeks i have had a couple of Harlequins die. With a large new tank and many fish i put it down to natural selection. Over the weekend I noticed one of my Discus eating a dead Harlequin. The next morning the Discus was floating around the tank disorientated, breathing normal and showed no physical characteristics of being sick. I immediately assumed that the discus had caught some think from eating the dead harlequin. I placed him in a hospital tank and treated with Metro. Within 4 hours the fish died. I spoke to the LFS and they could not enlighten me on the subject. Has any one experienced this before and know what the issue and solution is. I have now treated the large tank with a general antibiotic made by Wardleys.

[sammigold]

How new is your tank?

did you put alot of fish in at the same time or over a period of a few weeks?

What are your water parameters? ie. PH, KH, GH, nitrites, ammonia, nitrates?

If you can post some these details I am sure that someone will be able to help.

[DarrenJThomas]

The tank is about 4 months old. It is hi tech with co2 etc. The parameters are as follows

PH 6.5
GH 10dgh
KH 3dgh
Nitrate 1ppm
PO4 .25 ppm
Fe 0ppm
Temp 26.5

The fish from my old aquarium we introduced first. The new fish have been gradually introduced over the 4 month period.

[sammigold]

Sounds like you are doing the right thing..

Your discus might like a higher temp though.. they usually thrive around 28 to 30 degrees.
My suggestion is to keep a good eye on your fish to see if they display symptoms of anything. I had a problem in my tank at one stage with my black widow tetras. one died and I thought it was a one off and then 2 weeks later another one died and I noticed that his face was looking weird and then I discovered another one with half a face and I was looking at columnaris after medicating I managed to eradicate the tank of any further outbreak.
sometimes it is hard to diagnose problems with no physical symptoms. But if there is a problem a physical thing will turn up sooner or later.
Keep up with regular water changes to ensure that your water stays at optimum.
Maybe someone else will have some ideas. Good Luck!!!!! Sorry I can't help much. :?

[Merrilyn]

Darren, sorry to hear about your problems.

It's rotten when your fish die and you don't know the cause.

One thing I'd like to see you post, is your ammonia and nitrite levels for that tank.

There are diseases than can be passed on if a fish eats a dead tankmate, but I honestly don't know of anything that kills in less than 24 hours.

Are any of the fish showing any other symptoms, and have you lost any more small fish from the tank?

[DarrenJThomas]

Thanks for responding.

I have the following fish in the tank:

7 discus
3 rainbows
15 Harlequins
30 Cardinals
6 Catfish
5 Oto Algae eaters.

The tank is 860ltrs and I do a 400Ltr per week water change. As soon as the discus showed signs of illness i removed him/her and done a 400 Ltr water change on the tank and treated with a mild atibiotic. I dont have an amonium tester as i didnt think it would be a problem and suspect it will be extremely low. I also run a UV steriliser on the tank 24/7

The other fish do not show any signs of illness. The only other fish that have died would be 1 oto who died the day before the Discus. I think that fish also ate some of the dead fish. I think it is a disease caught from the dead fish and since the discus is a larger fish it has taken longer before death and therefor i have seen the symptoms.

[Merrilyn]

How long ago did you add the last new tankmate?

Is it possible it brought in some disease with it?

[DarrenJThomas]

The newest tank mates (Marlboro reds) were introduced about a week prior to the death of the discus. The other fish were dieing before the introduction of the Marlboros. These new fish had spent 2 weeks being treated with tetracycline and then spent 2 weeks in a holding tank as a quarantine measure. These fish show no signs of illness.

I checked the aquarium last night and there were no death and all fish showed no signs of illness.

[Merrilyn]

Hopefully you're on top of the situation now Darren.

Keep an eye on them, and let us know of any changes.

Good luck.

[DarrenJThomas]

Thanks for all you help