Urgent advice plz

[Katrina71]

My son was much younger when we started. We made it a practice to use a battery powered airstone when we did tank maintenance at first. It helped us to keep the fish and us less stressed until we got better with our routine.

 

[vetteguy53081]

Any aerosols or chemicals used near tank or in vicinity the last 48 hours? Also, Heater failure?

Check for stray voltage ( stick finger in tank- No you will not get electrocuted.... just feel tingling)
Lastly- Are you able to measure salt gravity with a different instrument? If not, have a trusted Pet store check for you

 

[Tamberav]

I just spoke to my son. He put 2mg Red Sea algae management and fed them with frozen food but he forgot to open the pump and skimmer back on. That may be the cause of oxygen deprivation?

Yes... Nopox increases the # of bacteria which will lower oxygen levels so dosing that plus forgetting the skimmer + pump could certainly suffocate fish.