Red tailed black shark help

[kieranJG]

Before we get into this I have all but given up hope of saving him but I down want to just give up on him

I brought a red tail about 2-3 months ago and all has been good it’s grown significantly and has been a very dark black with vibrant red.

I added some catfish last week (both died within a week but there was no issue with water parameters nor any other fish living in the tank

Now 3 days on from their death my red tails black has gone mostly grey white, his tail is very translucent and he keeps getting stuck upside down on the surface. My shrimp and dropping like flys but my other fish a completely healthy.

I’ve done multiple water changes, cleaned the sponges on two of the three filters running the tank and cleaned up the substrait but nothing seems to work or make a difference to the shark or shrimp

For reference my tank is a 110L grow out tank that I use for quarantine and shrimps set to 22oC.

Nitrates: 1 PPM
Nitrites: 0.9 PPM
pH: 7.3
dH: 12PPM
Ta: 118 PPM
Cl: 0PPM

Other fish are
a few small “Otto” catfish and two small goldfish that are being grown out for next spring

 

[Aiken Drum]

How are you able to test nitrate to a level of accuracy down to 1ppm? The lowest detectable level I've seen on test kits is 5ppm. What test kit are you using? Same for nitrite really. The tests can't distinguish to the level of accuracy you are reporting, they tend to go from 0.5ppm to 1.0ppm.

You are seeing nitrite and what appears to be very low levels of nitrate to be practically zero. You arent cycled. All the cleaning may be responsible for this, and the poor water quality may be the cause of your issues. What is your ammonia at?

 

[kieranJG]

I use a commercial photometer (I have access at work) not test strips hence the accuracy and I haven’t tested Ammonia to the same degree as the other fish are fine it’s just the shark and shrimp that are impacted

With being cycled the tank has been running for well over 5 years with ceramic beads to harbour beneficial bacteria in all 3 filters (I didn’t clean those only the sponges were cleaned with rain water)

I will use a test strip now and get back to you

 

[kieranJG]

I use a commercial photometer (I have access at work) not test strips hence the accuracy and I haven’t tested Ammonia to the same degree as the other fish are fine it’s just the shark and shrimp that are impacted

With being cycled the tank has been running for well over 5 years with ceramic beads to harbour beneficial bacteria in all 3 filters (I didn’t clean those only the sponges were cleaned with rain water)

I will use a test strip now and get back to you

nitrates: 0-9 PPm
Nitrites: around 1PPM
pH: 6.9
TA: 120-130
Cl: 0
Ammonia: 0
Did two test strips so all results are from me comparing colours so not amazing accuracy

Also forgot to mention the tank is planted

 

[kieranJG]

How are you able to test nitrate to a level of accuracy down to 1ppm? The lowest detectable level I've seen on test kits is 5ppm. What test kit are you using? Same for nitrite really. The tests can't distinguish to the level of accuracy you are reporting, they tend to go from 0.5ppm to 1.0ppm.

You are seeing nitrite and what appears to be very low levels of nitrate to be practically zero. You arent cycled. All the cleaning may be responsible for this, and the poor water quality may be the cause of your issues. What is your ammonia at?

I messed up my reply and it posted as a separate comment

 

[Andy Sager]

Usually when RT sharks get that kind of coloring, it's a water issue. Since you say there is no other fish being effected but you added some catfish that died, it may be that they brought in a disease or possibly the substrate or fertilizer you use is creating an ammonia level just above the substrate which is where the catfish and shark would be living. I'd get a water sample from the bottom of the tank just above the substrate and test for ammonia and nitrite. To do this, place a cap on the test vial and take it off when the vial is at the bottom of the tank. Replace the cap onto the vial then remove from the tank to test. ( you may need to remove some of the water from the vial if your tests use a smaller volume of water for accuracy. )
1 ppm of nitrite is toxic to fish. That is probably why the shark has turned that color. 0.5 ppm is the usual top limit to keep the fish alive.
In the meantime, try acclimating the fish into new clean water in a separate container/ bucket/ tank, garbage can/ etc so that you can rule out or in something in the tank itself vs a disease.

 

[kieranJG]

Usually when RT sharks get that kind of coloring, it's a water issue. Since you say there is no other fish being effected but you added some catfish that died, it may be that they brought in a disease or possibly the substrate or fertilizer you use is creating an ammonia level just above the substrate which is where the catfish and shark would be living. I'd get a water sample from the bottom of the tank just above the substrate and test for ammonia and nitrite. To do this, place a cap on the test vial and take it off when the vial is at the bottom of the tank. Replace the cap onto the vial then remove from the tank to test. ( you may need to remove some of the water from the vial if your tests use a smaller volume of water for accuracy. )
1 ppm of nitrite is toxic to fish. That is probably why the shark has turned that color. 0.5 ppm is the usual top limit to keep the fish alive.
In the meantime, try acclimating the fish into new clean water in a separate container/ bucket/ tank, garbage can/ etc so that you can rule out or in something in the tank itself vs a disease.

I was thinking of trying this but didn’t want to over stress the fish. Should I remove all the fish or just the shark as the others don’t have a care in the world still eating and acting completely normal.

 

[Andy Sager]

I was thinking of trying this but didn’t want to over stress the fish. Should I remove all the fish or just the shark as the others don’t have a care in the world still eating and acting completely normal.

I would start with just the shark since that is the one showing you a problem PLUS test that bottom water. If the water parameters between the new water and the tank water are similar or close to the same, you can acclimate him more quickly but if they are very different, acclimate him slowly using either a drip method or adding small amounts of new water to his container every 10-15 minutes vs every 5-10 minutes. If you need to do a slow acclimation, I suggest adding an air stone to the container with a gentle stream of bubbles. ( Too fast a stream will cause the pH to rise quickly. )