Guppy spinning in circles then hiding(staying at the bottom of the tank)

[Izzy101213]

Hi my brothers guppy(that I mainly look after)has been acting weird he would just hide at the bottom of the tank for hours then if you move what he's hiding under he'll start swimming then swimming round in tight circles multiple times in a row then find another hiding place,his colours also look duller then usual. Recently another fish has passed away in the tank, but he was not spinning or doing the same behaviors he just lay at the bottom of the tank and then then unfortunately passed away.I wonder whether he's stressed as it looks as if hes being picked on by the largest guppy a bit as the largest one is nipping his fins a bit but not loads.Do you know why?

 

[JuiceBox52]

What size tank?
What fish are in the tank?
Ammonia?
Nitrite?
Nitrate?
What is your GH? You should be able to find this on your local water providers website.


Do a 75% water change every day for 2 weeks.

Post a video or picture. If the video is too large post it on YouTube and give us the link

 

[Salty&Onion]

Everything is covered by @JuiceBox52
But... for how long was the tank set up? Did you cycle it? How did you cycle it?