One tiger Oscar out of two passed.

I recently moved my two tiger oscars into there 55 gallon tank.. I let it cycle through and it’s been a couple weeks since they’ve been in there,, I noticed the one was being dramatic and want as outgoing and would lay at the bottom more this past couple days.. last night I got home and it was stuck to the filter so I gently scooped him off and he was gasping for air as you could tell wuth his mouth and gills and continued to get stuck as I’d continue to unstick him… this morning he was stuck and when I unstuck him he was no longer breathing or anything.. I did dispose of him but now I am concerned for the other fish. The other fish as of last night did start to mope around. I am fairly new as well… I do have a 90gal rated filter so I was unsure if it was over oxygenating the tank. Is there anything I can do or did do that I shouldn’t have?! Help please!!!

 

Could you please fill out the emergency template? A 55 is a little small for two Oscars IMO and I highly doubt over oxygenating was the cause of death.

 

Be a good idea to test for ammonia.

 

Test your water, do a water change, and report back with the emergency template so we can help troubleshoot further

 

Tank
What is the water volume of the tank?
How long has the tank been running? 1 month aprox
Does it have a filter? Yes rated 90 gal
Does it have a heater?yes
What is the water temperature?aprox 79F
What is the entire stocking of this tank? (Please list all fish and inverts.) two oscars (now the one)

Maintenance
How often do you change the water? By weekly
How much of the water do you change? Roughly 50%
What do you use to treat your water? API stress coat algae fix and water clarifier
Do you vacuum the substrate or just the water? Both

*Parameters - Very Important
Did you cycle your tank before adding fish? Yes apron 4 days
What do you use to test the water? API TEST KIT


Feeding
How often do you feed your fish? 2-3x daily
How much do you feed your fish? Pellets /flakes
What brand of food do you feed your fish?
Do you feed frozen?no
Do you feed freeze-dried foods? Shrimp

 

Could you please list the parameter numbers? 4 days is not enough time for the tank to have completed the nitrogen cycle, unless using seeded media. Gasping for air is usually a sign of ammonia poisoning, and lethargicy can be another sign as well.

If the fish keep getting stuck to the filter like you said I would baffle it.

 

Proceeding with the assumption that your tank is not yet cycled, you need to do daily water changes to try to protect your fish from ammonia/nitrite buildup. Use your test kit to monitor levels, and keep doing big water changes until your tank is cycled (reading zero ammonia and nitrite, and started to produce nitrate.) Read up on the nitrogen cycle to learn more. You may also want to decrease feedings to lower the amount of waste in the tank.