Whats Wrong With My Guppys?

So 2 weeks ago I bought 7 guppys and put them in a 1 week cycled 10 gallon tank for quarantine. I had a lovely silver guppys that ended up dieing from nothing... Now today I just had another die from fin rot. But this guppy looks like he has clamped fins but his belly looks weird. Is it parasites? I just saw him eat the last two days though... I will do a water change and test the water right now. Is this just common for guppys to always have diseases or I'm I doing something wrong....

 

Males are usually thinner than females, but he does look a little too thin.

Does he swim normally or does he swim in the same spot whilst doing a little wiggle?

Guppies.. it depends on the breeder really, but usually with good water conditions issues never rise. What are your parameters?

 

Males are usually thinner than females, but he does look a little too thin.

Does he swim normally or does he swim in the same spot whilst doing a little wiggle?

Guppies.. it depends on the breeder really, but usually with good water conditions issues never rise. What are your parameters?

I need to test my water, but he swims with the others guppys... And they are all male from a petstore

 

I need to test my water, but he swims with the others guppys... And they are all male from a petstore

Please give me all the parameters you can such as ph, temperature, ammonia, nitrite, nitrate, hardness (does limescale build up on your sink and shower?)

 

Please give me all the parameters you can such as ph, temperature, ammonia, nitrite, nitrate, hardness (does limescale build up on your sink and shower?)

Sorry I was super busy, there is a little bit of white stuff on sink tap (laundry room sink) but it never affected my other fish. (My house is only 2 years old so shouldn't be to much of an issue) heres the results my ammonia is usally just between 0.25 and 0 for some reason. I tested all my tanks and tap water... Ugh my photo was the test results didnt get sent to my email! Its on my phone but I can't get to it until afternoon