Dying Danio?

[adrianborg]

Hi all,

Lost a zebra danio today, my first fish death. Another is hiding in the roots of the anubias barteri, panting but looking otherwise normal. This worries me, as it's notmally very active. Should I remove it from the tank?
I have no idea why the other one died. The dead fish looked absolutely normal - no marks/swellings/damage.

I know this is know helpful - no real symptoms to speak of except for death in one and lethargy in the other, but has could anyone have any clues what's going on? All other fish in the tank look healthy and active.

I did put some frozen peas in yesterday which I had boiled for about a minute - they're for the BNs but the danios always jump on them. Could this be related?

Tank size: 4' (240 litre), heavily planted, plus bogwood. Co2 dispenser for the plants. Lighting+CO2 only 8-9 hrs per day.
Age: about 3 months
Water changes: 40-50 litres every week
Chemical additions: nutrafin aquaplus in recommended dose, for all new water that goes in; occasional ferts (sera florena liquid or sera flore tablets)
Temperature: 25-26
Nitrites: zero
PH: 7.5-8.0; water is hard
Filter: Fluval 305 external (1000 l/h)
Stocking: 5 zebra danios (now 4 including the "sick(?)" one), 4 leopard danios, 6 harlequins, 5 bristlenoses; the danios were the first fish in the tank. There are also a number of ramshorn snails.
Feeding: normally nutrafin flakes every 1-2 days, occasionally freeze fried bloodworm or daphnia; pleco flakes & occasionally peas/cucumber for the BNs after lights-out which I remove within 2-3 hours

 

[afremont]

Hi all,

Lost a zebra danio today, my first fish death. Another is hiding in the roots of the anubias barteri, panting but looking otherwise normal. This worries me, as it's notmally very active. Should I remove it from the tank?
I have no idea why the other one died. The dead fish looked absolutely normal - no marks/swellings/damage.

I know this is know helpful - no real symptoms to speak of except for death in one and lethargy in the other, but has could anyone have any clues what's going on? All other fish in the tank look healthy and active.

I did put some frozen peas in yesterday which I had boiled for about a minute - they're for the BNs but the danios always jump on them. Could this be related?

Tank size: 4' (240 litre), heavily planted, plus bogwood. Co2 dispenser for the plants. Lighting+CO2 only 8-9 hrs per day.
Age: about 3 months
Water changes: 40-50 litres every week
Chemical additions: nutrafin aquaplus in recommended dose, for all new water that goes in; occasional ferts (sera florena liquid or sera flore tablets)
Temperature: 25-26
Nitrites: zero
PH: 7.5-8.0; water is hard
Filter: Fluval 305 external (1000 l/h)
Stocking: 5 zebra danios (now 4 including the "sick(?)" one), 4 leopard danios, 6 harlequins, 5 bristlenoses; the danios were the first fish in the tank. There are also a number of ramshorn snails.
Feeding: normally nutrafin flakes every 1-2 days, occasionally freeze fried bloodworm or daphnia; pleco flakes & occasionally peas/cucumber for the BNs after lights-out which I remove within 2-3 hours

The obvious question is how about the ammonia levels? Sitting still and panting is pretty serious. Can you put him in a hospital tank of fresh water, or even a bucket with an airstone to see if there's a sudden improvement?

 

[adrianborg]

I don't have an ammonia testing kit, and no chance of getting one at this time on a Sunday. I did an 50 l water change yesterday. If it was ammonia, do you not think the other fish would be suffering as well? They all seem quite happy.

 

[N0body Of The Goat]

Leopard and Zebra Danios are not going to thank you for a constant temp of 25/26C, they are sub-tropical fish that should spend most of the year in the 18-20C ballpark. They could simply be "burning out" from a constant state of hyperdrive metabolism, perhaps combined with not enough strong water surface rippling to keep the oxygen levels as high as possible.

You could reduce the heater thermostat right now to 21C (proving it is calibrated well) and let the water naturally cool over the next day or two with no problems for any of your fish, but given the gasping danio, I would do ~50% wter change of similar temp water aswell ASAP.

 

[adrianborg]

I don't have an ammonia testing kit, and no chance of getting one at this time on a Sunday. I did an 50 l water change yesterday. If it was ammonia, do you not think the other fish would be suffering as well? They all seem quite happy.

New development... he's up and about now, swimming with the others. But still opening and closing his (her?) mouth.. am I worrying about nothing? Is it possible he's just stressed because I had my arm in the tank fishing out his tankmate?

 

[adrianborg]

Leopard and Zebra Danios are not going to thank you for a constant temp of 25/26C, they are sub-tropical fish that should spend most of the year in the 18-20C ballpark. They could simply be "burning out" from a constant state of hyperdrive metabolism, perhaps combined with not enough strong water surface rippling to keep the oxygen levels as high as possible.

You could reduce the heater thermostat right now to 21C (proving it is calibrated well) and let the water naturally cool over the next day or two with no problems for any of your fish, but given the gasping danio, I would do ~50% wter change of similar temp water aswell ASAP.

NObody of the Goat - thanks for this advice. Not so worried about the oxygen as the filter outlet provides good surface rippling and oxygen in the water. I hadn't seen your reply when I posted the "new development" reply above; since he seems to have perked up a bit,I'll see how he goes through today and if he relapses I'll follow your advice on the temperature drop. Will do the water change straight away either way.