Don't know whats wrong.... need assistance please!!!!!

[pink66]

my display tank is 5x2x2 with sump filter system.
occupants - 1 discus (more in QT), 2 bol. butterflies, 10 harlequin tetras, 6 assorted cories and 5 (well maybe not anymore) koulie loaches.
tank has been up and running since middle of July. water is nitrate 0 nitrite 0 ammonia 0 ph 7.2 (stable). water changes 50% once per week. also 3 times a week I vac up any left over beefheart/seafood mix and poo.

All was well, one cory went very quiet one day and the next day was dead. :cry: :cry: No obvious symptoms. I spent ages watching him in the tank. That was Saturday.. Today I found a koulie on the sand (very unusual) and it was quiet and having trouble keeping balance.. Immediately removed him to the hospital tank for observation but he is not looking good. :? :? his breathing seems slightly laboured but apart from that all looks normal..

All other fish both large and small are zooming around the tank and are eating as normal.. I am at a loss to explain this and if indeed it is a pattern want to stop it before it gets to Finn.

Any suggestions would be greatly appreciated

[pink66]

In my tank I have an area of river pebbles.. I vac these as well but with limited success.. As the fishies in questions are bottom dwellers I am concerned that if any little food particles (especially since I am now feeding the BH/seafood mix may be getting caught and they are eating them.. So as a precaution I am now removing them from the tank and extending the sand for easier cleaning.. (I was wary when I first put them in but figured I could keep them clean) :banghead .

I have taken sooooo long to get this far with discus and I am not going to stuff it up now...

So with that variable out of the picture I am still open to any suggestions as I cannot be sure this is the cause..

[Merrilyn]

You're doing everything right Sharon. There's no obvious reason why you should have lost those two fish, so I feel it's just a very unfortunate coincidence.

There's just one thing I would query, and that's the zero nitrate reading. A fully cycled tank should have some reading of nitrate, even if you've just done a big water change, it should still show some kind of reading.

Just do another water test, and let us know if you are finding ANY amount of ammonia or nitrite.

[pink66]

thanks Merrilyn, 3 more koulis are missing in action but they are hard to find at the best of times.. so they are counted as MIA at the moment.. I did find one quite happily living in the sump though not sure how he made it through all the media i have in there but lucky for him he did. :lol:

I know, the lack of nitrate has been puzzling me since set up. (my cichlid tank (much larger population 4 ft and fluval 405) always shows a small reading - I also do not clean this one as often as the discus tanks) the only time I have ever showed the smallest reading was when I was stinking the place out with prawns in the tank during cycling. even then it was only just registering on the test. the ammonia went thru the roof and then as it dropped off up came the lowest reading of nitrate (the test kits are all new). I have not been able to register a reading since.

My tank is very, very lightly stocked at the moment (and since taking all the river pebbles out and doing a major water change much cleaner too)
I did a full test range yesterday and still no reading.. could it be the sump (it is the first time I have ever had one of these.. usually i have a cannister (all my other tanks do))

I was sitting down with a cuppa today and I must say all the fishies still in the tank look just happy and active and still eating like little piggies.. so daily monitoring i suppose will be the name of the game..

[Merrilyn]

Yes I think so too Sharon. Just observe for the time being.

The low stocking rate, and the frequent waterchanges could account for your lack of a nitrate reading.