Black ghost knife gasping

[Agill]

I have a BGK that is about 6 inches long, I also had a 12 inch one. I lost the large one yesterday, they were both gasping, I checked my levels nitrites were .5: nitrates 20-40, no chlorine and 0 ammonia. They eat cut up shrimp and bloodworms. Any ideas why my little one would be gasping? Tank temp is 79-80, I have 2 air filter pumps and 2 bubblers going. I'm new to having BGK, I also have 2 angels with him and they are fine, no signs of stress. Any advice would be great I don't want to end up losing both.

 

[Byron]

I have a BGK that is about 6 inches long, I also had a 12 inch one. I lost the large one yesterday, they were both gasping, I checked my levels nitrites were .5: nitrates 20-40, no chlorine and 0 ammonia. They eat cut up shrimp and bloodworms. Any ideas why my little one would be gasping? Tank temp is 79-80, I have 2 air filter pumps and 2 bubblers going. I'm new to having BGK, I also have 2 angels with him and they are fine, no signs of stress. Any advice would be great I don't want to end up losing both.

Nitrites (with the "i") should be zero in a cycled tank, so any increase is cause for concern. BGK being sensitive fish (to water) would show it before angelfish, though these are going to be having problems too. I would do a major water change, use a good conditioner; one that detoxifies nitrite would help [Seachem's Prime, or Aquarium Solutions Ultimate both deal with nitrite for 24 hours]. These should be daily until nitrite is zero (and nitrates hopefully lower than they are).

Nitrate above 20 ppm is going to cause the fish some stress, so while this is not likely the cause it is a facor in the overall picture. Is this normal, or is this higher than normal? I'm wondering if something has caused a "mini cycle," for lack of a better word. I have known medications that affect bacteria to do this, or toomuch food, dead fish...consider all possibles.

 

[Agill]

The levels are fairly normal for this tank, I did a 25% change, using safestart + with the new water on Sunday, signs of gasping started Tuesday morning. I did another 25% change Tuesday after getting test results and added Seachem Prime. Lost the large BGK after these attempts. My small one is still hanging on but looks to be struggling.

 

[Byron]

Assuming there is not something in your tap water doing this (test it for ammonia, nitrite, nitrate), major water changes of at least half the tank volume are the best way to respond when respiration is rapid/difficult. If you see this lessen after the water change, good.

Is the substrate cleaned during water changes? Filter cleaned regularly? Just some more possible factors.