40 Gallon Tank Red tailed shark breathing very heavily

Hi all, looking for your guidance. I have a red tailed shark who is close to 11 years old. He has not eaten for last 2-3 days. He had a fungus like growth close to the mouth. I was doing Pimafix and Melafix treatment for last couple of days. That fungus growth seems to be gone but he is breathing extremely hard and keeps coming up to hit the water surface which he never used to do. Today, I did a 40% water change and started the Kanaplex treatment. Water readings also seem to be fine. Nitrate is at a higher side and close to 40 but that has always been the case with this tank. Its a 35 gal tank. Pls guide.

 

Do you have any pictures?

 

How are things like surface agitation? Anything change recently as far as oxygenation of the water?

 

It seems likely that the disease has damaged the gills.

I expect that, like older people, older fish are more susceptible to infections due to lower resistance late in life.

 

Hi all, really appreciate the inputs.

• Regarding increasing the oxygen content in water, I had a smaller (ring) airstone which I have now replaced with a bigger one. Pic attached.
• I have been using this Aquaclear 50 filter. As of now, I have removed the charcoal layer (middle) so there is bottom foam layer and the topmost bio layer. I clean the foam layer as it gets dirty (by using some of the tank water) but I haven't changed the topmost bio layer for a while now. Pls share if I need to make any changes here.
• As I mentioned above, I gave the first dose of Kanaplex Wednesday night after the water change. I had also added aquarium salt as per the dosage mentioned. Waiting for ~48 hrs to give the second dose. Hopefully, it will come to that. He seems to have lost all his energy due to not eating and constant gasping.

 

Hi, I gave the second dose of Kanaplex today. Still no improvement in her condition. She is sitting in a corner of the tank and breathing very heavily. Also, not eaten for last 4-5 days.

 

There may not be much that you can do now. Observe and be ready to euthanise if you think she's suffering too much. You've obviously cared for her very well to reach an age of 11 years. I've never heard of one living that long and you should be proud of that. BTW she's a rainbow shark not a red tailed shark. A close relative.

 

With filters I try and keep the maximum amount of biological activity (dirt) as possible without the flow being impeded excessively. That way more ammonia can be dealt with. It is important to avoid the flow being impeded as reduced flow could mean less oxygenation. Over time you will get to know the optimal frequency of cleaning.