Why Do My Fish Keep Dying, Only In This Tank!?!?!?

[Glegorly]

Whenever I put fish in this specific tank, by the morning they are always dead. I've put 3 White Cloud's in there and they all died overnight, I've put a Betta in there and he died over night and I put 4 Cardinals in there overnight and this morning two are dead and the other two are really calm.

It's a 2.5 Gallon that I've been using as a quarantine when fish become sick. But once they recover, I start the tank again (not the filter) but gradually replace the water in it over the course of a few days adding dechlorinator in required amounts.

After the betta died I cleaned the tank out thoroughly with hot water and scrubbed it clean and cycled the tank properly again. There is no gravel, but two plants in it from one of my main tanks. Temp is normal, and all water stats are normal. I just don't understand what keeps going wrong!?

The cardinal's were fine this morning when I woke up at about 10am, and now at 1pm they're either upside down and swimming, laying on the bottom or just slowly swimming the tank. It's happened so suddenly.

What am I doing wrong!?

 

[WILDER]

When you move the fish to the hosptial tank are you matching ph and temp.

Best to steralise the tank after use.

Swimming upside down can be swim bladder, bacterial infection, ph shock, the fish is dying.

 

[Glegorly]

When you move the fish to the hosptial tank are you matching ph and temp.

Best to steralise the tank after use.

Swimming upside down can be swim bladder, bacterial infection, ph shock, the fish is dying.

Yup, when I move any fish to any tank I always acclimate them properly. I put some bacterial infection meds in last night. I'm not sure what it is, but every fish that gets put in it has similar symptoms (listlessness, death within hours). How would I go about steralising an entire tank?

Thanks for the help =]

 

[Colin_T]

I doubt it's a disease. I would be more inclined to think it is something you are putting in the tank, probably the water.
Do you fill the tank up with tap water before you add the new fish and how long is the water in the tank before the fish are added?
Do you use a water conditioner/ dechlorinator?
What gravel do you have in the tank?
Is there a heater and thermometer in the tank and are they working correctly?
Do you have an established filter that you add to the tankbefore or after you put the fish in there?
Do you feed the fish after they have been put in the tank?

 

[Glegorly]

I doubt it's a disease. I would be more inclined to think it is something you are putting in the tank, probably the water.
Do you fill the tank up with tap water before you add the new fish and how long is the water in the tank before the fish are added?

Yes, Before I put the cardinals in there it had been set up and running for about three-ish weeks without any fish.

Do you use a water conditioner/ dechlorinator?

Yes, but it's running low so I applied a smaller amount than recommended only because I have three tanks to run and I'm not to sure when I'm going to get the chance to run down to the LFS.

What gravel do you have in the tank?

I removed it to make tank maintenance easier.

Is there a heater and thermometer in the tank and are they working correctly?

Both and yup, they work fine.

Do you have an established filter that you add to the tankbefore or after you put the fish in there?

I let the tank run with an empty filter for a few days to aerate the water and let the dechlorinator take effect and then add filter media from my main tank.

Do you feed the fish after they have been put in the tank?

No, I have tried to shortly after I added fish before but they weren't interested so i removed it.

 

[WILDER]

When the tanks empty with no fish do you run a filter or turn it off.
Does the water smell bad when you add the fish.
I once turned a filter and heater off in an issolation tank till I stripped it down and the water stunk.

 

[Glegorly]

When the tanks empty with no fish do you run a filter or turn it off.
Does the water smell bad when you add the fish.
I once turned a filter and heater off in an issolation tank till I stripped it down and the water stunk.

When it's empty I usually leave it on to keep the water moving, but I turn the heater off (I need the plug sockets! ). It smells faintly and sort of like some kind of herbal tea, I'm not a fan of herbal tea and I can't drink it because it reminds me of fish tank water .

 

[WILDER]

Is the sponge still in the filter when you turn the heater off.
Benefical bacteria will die off if you are turning the heater off.