Guppies dying

[32Chop]

In one of my aquariums all of my guppies are dying. All of the other fish are fine and show no signs of disease or stress. I have had the guppies for over 6 months. My nitrates have been climbing over the last few months. They are usually between 20 and 40. Nothing has changed in my lighting, fertilizer dosing and if anything I am feeding less than usual. My plants are growing like crazy.

Tank: 150 gallons

Lighting: Fluval plant 3.0

Fertilizer: Easy Green 1 pump for every 10 gallons

Water:

Ammonia 0

Nitrate 80

Nitrite 0

GH 150

KH 100

PH 7.0

[Cory]

When was the last water change? What is the PH out of the tap? 

[32Chop]

My last water change was 4 weeks ago. My ph out of the tap is 6.5. I am running 2 full media bags of crushed coral in my Fluval FX6 which gets my ph up to 7.0 to 7.2. I have always done water changes every 4 weeks and this is the first time my nitrates have jumped to 80. The nitrates usually sit between 20 and 40. I am not always able to get the dead fish out of the tank because they end up in the caves, plants and crevices that I created for the fish. 

[Brandy]

Do they have any symptoms before they die? what else (livestock) is in the tank?

80ppm nitrate is high, but I thought guppies were among the more tolerant species for things like that. Even if you'd had an ammonia spike they should have been ok I would expect unless they are a super fancy strain...what is your temperature?

[32Chop]

There are no symptoms at all. No physical signs and still swimming around fine.

They aren't super fancy guppies. red sunburst, blue cobras and some regular fancy guppies

Water temperature is 76-78 degrees

I have the following fish:

6" sail fin pleco

3" gold fin pleco

2" super red bristle nose pleco

1 neon tetra

1 medium angle fish

4 small angle fish

1 golden chinese algae eater

1 rainbow shark

2 albino corydora

1 salt and pepper corydora

1 dwarf grommie

3 danio not sure what color

10 amano shrimp

 

Edited October 1, 2020 by 32Chop
forgot something