Angel fish behaviour

[louis jumped]

I haven't checked in recently so I apologize if this topic has been discussed already.
My tank is 120 gallons. Undergravel filter with 2 power heads. Set up for 1.5 years.

Community:
3 angels. two are a breeding pair
3 gouramis
7 various tetras
2 platties
3 cory cats
1 sailfin pleco

The female breeding angel fish has spent the last week hovering in the wake of the power head outflow. She eats well but her strength is failing as she is constantly swim against the current. The water tested today at 7.5 pH and 12.5 nitrates and 0 nitrites. The fish store people were puzzled by this behavior. They thought maybe an irritation or infestation in the gills so i treated the tank with Prazipro. Hard to watch this beautiful creature weaken before my eyes.
Any ideas would be appreciated!

 

[Zagz]

Does she show any physical signs aside from her swimming behaviour? Any bloating, abnormalities in her fins or scales?

 

[louis jumped]

Thanks for asking! I forgot to mention, the social scene consists of her breeding partner staying close by and chasing away the third angel when he (?) gets close. No other problems from any other tankmates that I can see. Her colors were pale last week, getting more vibrant. Her breathing is fast and labored. I don't see anything unusual around her fins.

 

[Zagz]

When was your last water change? Have you tested for ammonia nitrite and nitrate recently? With undergravel filters, over time I have found they can be nitrate factories. Do you clean under the filter ever?

 

[louis jumped]

I changed the water on Jan. 14. I tested it today (see first post) and forgot to mention there was no ammonia. Maybe there is something lacking in my cleaning technique-- however when one fish is in distress and the rest seem OK I am reluctant to embark on any major endeavors in the tank. That's the thing I guess, keeping a balance. thanks for your question.

 

[Zagz]

Are you using test strips or liquid tests? If you haven't done a water change since dosing the medication I would do one. If her colors are coming back and her only symptom is breathing, I would do the water change. Do you have an airstone in the tank? If not I'd consider putting one in.

 

[louis jumped]

I used to have an airstone. Why would you recommend one?

 

[Zagz]

Sometimes the fish breathe laboured as a result of lack of oxygen in the water. I have had many fish breathing heavily stop within a couple of hours of adding an airstone or lowering the water level a bit.

 

[louis jumped]

The most recent thing I did in the tank was replace the air tubes that connect to the top of the power head. There are two power heads. Last week, one of them stopped working. The airway had become blocked -- it was white in color - calcium deposits maybe? Anyway it stopped adding air into the tank so I replaced the tubes on both power heads. That was when the angel started this behavior. Seems like I am adding more oxygen to the tank now.

 

[Zagz]

That is strange. Not sure if there could be a connection. As long as there is oxygen in the tank from the powerheads then that is good. I'd see how she reacts after the water change. Perhaps she is on the mend as her colors are coming back.

 

[louis jumped]

Yes I hope she is one the mend. I'll keep you posted. Thanks!