Only Guppies Dying

[wildwolf701]

I have a 55 gallon fish tank it was perfect and I been had guppy fry but an ice storm came through and knocked out my power for 3 days, I lost all my fish. After getting power back I cleaned out the tank and tested the water a few days later ammonia 0 I don't remember the nitrites or pH but I know it was the same as before they died. After letting it run for a couple of weeks I got 2 albino algae eaters, 10 neon tetras, 5 zebra danios, 2 dalmation mollies, 1 red tailed shark, and 10 guppies. Now 3 days later all of my guppies are dying a few a day they go from looking, swimming and eating perfectly to a few hours later dead or dying slowly. I only have 4 left and I'm not sure if its the guppies sick or my tank but every other fish is doing great. I'm needing some advice asap.

 

[Ninjouzata]

Sorry for your losses 

 
What are your water parameters? (pH, ammonia, nitrite, nitrate)
How long was it running before you got more fish? I take couple as two weeks but am just checking cause your use of couple and mine could vary.
 
How did you acclimate the fish to the tank?

 

[bluesword23516]

Also look for anything unusual on the fish. Any worms, scratches, or fin nipping/ clamping

 

[Blondielovesfish]

Do they show anything unusual before dying? i.e. heavy breathing, not eating.
 
You say you let it run for a couple of weeks, did you add a source of ammonia during that time? If not, your tank will probably be going through a mini cycle (or a full cycle, depending on how much bacteria survived during the power cut). 
 
If you can get the ammonia, nitrite and nitrate readings like Ninj asked for then that would be very helpful

 

[wildwolf701]

Ammonia is 0, nitrite is 0, and pH is 7.2. They were eating and swimming fine then just started swimming slow and kind of floating then they die. Now I have 1 zebra danio doing it. They don't have anything on them until they start to die and my other fish will start eating them.

 

[Blondielovesfish]

How much and how often are your water changes?

 

[wildwolf701]

About 25% every other day

 

[Blondielovesfish]

Do you add dechlorinater?

 

[SimpleDog]

What was your nitrate level? 

 

[wildwolf701]

Yes I add declorinater.