40 Gallon Tank Fish breathing heavy

[HeathC]

Hi, my guppies and plecos have recently been breathing very heavily. I don’t think it is an oxygen issue as I have 3 air stones and 2 sponge filters +canister in my 35 gallon (130 litre). I don’t think it is an ammonia issue as I have 0-0.25. Could it be gill flukes?
My guppies gills are a bit red (mainly in the females though). I was thinking of treating the tank with praziquantel. What are your thoughts?
Thanks Heath. (Also my tank is overstocked as I breed lots of plecos)
I think I posted this in the wrong thread oops. Does anyone know how to move it?

 

[BigManAquatics]

Pictures might help, if possible.

 

[HeathC]

Here’s some although they are pretty bad quality

Pictures might help, if possible.

Just added them

 

[BigManAquatics]

I would do a couple of 50% water changes first, see if that helps the breathing, before treating. That's just me, though.

 

[LowConductivity]

Ammonia 0-.25... nitrite measures...?

 

[HeathC]

Ammonia 0-.25... nitrite measures...?

Nitrite is 0. I’ll test nitrate this afternoon

I would do a couple of 50% water changes first, see if that helps the breathing, before treating. That's just me, though.

I did a 50% yesterday but I’ll do another in 1-2 days to see if that helps