Fish all dying!

lenalover

I have 3 tanks, a 44g, a 20g and a 10g.
When I first put fish into the 44g, around 10 guppies died within the first week. I had guppies, cories, a betta and a gourami in it.
When they were dying, they looked like they were gasping for air, their gills were moving really quick.
All the guppies died, except one, I filled the 20g, and put him in there. He is healthy now.

I tested the 44g's water for ammonia, and nothing. The pH is 7.0.
Today, the betta died, the gourami hasn't been eating, and the cories are pale.
I did a 25% water change, and added more circulation.

I use the same water for all the tanks, and the two smaller tanks have had no problems.
The only difference is that in the 44g, I have sand, live plants, and driftwood. The other tanks are all fake. Could that make a difference?

Thank you!

AbbeysDad

What was the history of the 44g tank - was it cycled - established? What was the filtration and/or aeration?
What was the temperature? Were there other fish in there before the guppies?
More information is required.

lenalover

It had only been running for 4 days when I added the fish, because a disease broke out in the 20g, so I had to move them. It's been running for probably 3 months now.
I have an Aquaclear50 filter, and a 60gallon air pump.
The temperature is 77-78. I added all the fish at pretty much the same time.

AbbeysDad

You moved them because of disease in the 20g - what disease? Are you sure that didn't kill them?
A 60g air pump???

lenalover

^^ They had some sort of fungus, I'm not sure which kind. I moved all the ones that didn't have it, and they didn't get it.
I have a Whisper air pump that is for up to 60 gallons. And, a small air stone and large long one.

kitten_penang

i would suspect ammonia poisoning since it wasn't full cycled plus the addition of so many fishes all at once must have caused the water to go off thus killing the fishes

lenalover

^^ I thought that too. I tested it, and there was no ammonia.

Calmwaters

What type of test kit did you use?

lenalover

^^
I used this one: Aquarium Pharmaceuticals Ammonia Test Strips - Test Kits - Water Conditioners - PetSmart

kitten_penang

anyhow i would suggest you get ro water..remove 30% an add in the ro.add air stones and a active carbon to the filter just in case