HELP! 3 guppies dead in 4 days

[ChloesQuestions]

This is my second post. Recently in the past 4 days (including today) 3 guppies dropped dead, showing no symptoms of any sickness. They did lose a tiny bit of color and had strange poo.

Tank size: 20g
pH: unknown (gonna get tested tommorow)
ammonia: 0
nitrite: 0
nitrate: 0
kH: not tested yet
gH: not tested yet
tank temp: 74-80 degrees f

not many symptoms
Lose of color
Not moving much
Back bent

ALL the snakeskins died

1 kulhi loach, 2 rasboras (ik its not many but i will get more), 3 neon tetras (will get more), 1 BABY goldfish, 2 other guppies (due to them dieing, 1 male 1 female right now)

Please help!

Another guppy with sickness is my pregnant guppy.

Symptoms:
Slow,
Not moving much,
WHITE and CLUMPY poo
also clear and stringy

is this parasites? (NOTE this IS a PREGNANT guppy)

 

[ChloesQuestions]

woops i put nitrite and nitrate at 0 (i am not sure what they are at but the water was tested fine)

 

[eaglesaquarium]

woops i put nitrite and nitrate at 0 (i am not sure what they are at but the water was tested fine)

What is 'fine'? Zero is the only 'fine' there is for nitrite. Nitrate can be in the 20s and be ok, but nitrite being anything other than zero is not fine. You will need to know this number.

You will also need to know the kH and gH number. This should be available from your local water supplier. Based on the other fish not showing much trouble but the guppies, it is highly likely that the water is on the very soft side. The other fish are from soft water, but guppies prefer harder water.

In general, soft water fish fare better in hard conditions than vice versa.

 

[ChloesQuestions]

i dont think nitrite is above 0 (im not using caps or grammar because im in a hurry)