Roseline Shark Sitting On Bottom Of Thank.

[Larryv]

Tank size: 75 Gallon
pH: unsure of pH or other levels - noticed the problem after hours and cannot get to pet store for a new kit until after work tomorrow
tank temp: 75 Degrees F

Fish Symptoms (include full description including lesion, color, location, fish behavior):  One of my Roseline sharks is sitting on the bottom of the tank.  I was able to get it to move and it seemed agitated, and seemed to have difficulty keeping it's tail end up and horizontal.  Its belly is slightly large, though not enough to appear sick.  Could it be about to give birth, or is it more likely sick?  I have not checked PH (I have to pick up a new kit after work tomorrow).  However, the water temp is 75 degrees and the tank is very well established.  All other fish appear to be fine.  The Roseline has no discoloration or additional signs of illness.  The fish are about 4-5 years old now.  Thanks.

Volume and Frequency of water changes:  I change out 5 - 10 gallons every month or so.  The tank is well established and has not had chemical imbalance issues, etc. since it was set up about 5 years ago

Chemical Additives or Media in your tank:  I have carbon based filter (Emperor filter)

Tank inhabitants:  3 Roseline Sharks, 3 Clown Loaches, 1 Dwarf Pleco, 4 Khuli Loaches, 1 live plant in addition to plastic plants, logs, etc. 

Recent additions to your tank (living or decoration): None

Exposure to chemicals: None

Digital photo (include if possible): NA
 

 

[Lunar Jetman]

If this is something to do with the water it's unlikely to be ph related and more likely to do with ammonia, nitrite or nitrate levels. If you don't have a test kit I would suggest carrying out a water change (40-50% would be good) as a matter of course in case there is something wrong.
 
How long has the tank been set up and have you changed anything recently, e.g. filter, substrate, etc. You say the fish are 4-5 years old so have they always been in this tank?
 
It doesn't sound too healthy to me but until you start ruling out things, e.g. ammonia high, then its difficult to pinpoint the cause of the issue.

 

[the_lock_man]

It's certainly not about to give birth, because it lays eggs.
 
My initial suspicion is that you have a very high nitrate level in your tank. I personally carry out water changes of about 30% every week. You are doing a maximum of 1/3 of that, at a ¼ of the frequency. I suspect that the build up of nitrate is starting to affect the fish, and will only get worse.
 
You would be best off confirming this with a test kit (liquid, not paper), but don't get the API, it can often give false 0 results.
 
Assuming I'm right, you need to get the nitrate level down to around 10-20ppm above your tapwater level (so you need to test that too ). However, the other issue is that over the last 5 years, the other fish have got used to having a high level of nitrate in the tank, and to quickly remove it all could easily shock them, potentially fatally.
 
Obviously, without knowing how much nitrate you have, it's difficult to give you a water change schedule that will work, but I'd suggest to start off with, do 10% today and tomorrow, do another 15% on days 3 - 5, then 20% on days 6-7. After 7 days, test again, and see where you are. If necessary, continue changing 20-25% daily until you reach a suitable level.
 
From thereon in, you need to be doing weekly changes, to prevent it happening again.

 

[Larryv]

Thanks for the replies.  I grabbed a new test kit today and nitrates do seem to be the issue.  I had been diligent about testing the water for a few years, and after never seeing any problems, I got a bit lax on that.  The folks at the local fish store told me to do a 30% water change today and again tomorrow.  I performed the 30% change today and went from a nitrate reading of 80 down to what appears to be a bit under 60.  I can see the issue of the other fish learning to live in a higher nitrate environment, so I may slow it a bit and not do another full 30% tomorrow.  I'll probably drop down to 10% tomorrow, and then go up slowly from there.  

 

[N0body Of The Goat]

Your infrequent and small water changes are quite possibly a factor in this and the nitrate results you are getting could be way below reality... The test reagents come of of solution and form a sediment at the bottom of the bottles, you really have to shake/bang bottles for a good minute or two to have any hope of something in the real ballpark.
 
However, if you have always kept these Redline Toepedo Barbs at 75F under normal conditions, I'm afraid you could be seeing the first of the group dying prematurely of old age. These fish have not evolved in permanently tropical waters, the rivers they come from vary from ~15C in the winter to ~25C in the peak of summer. Keeping them at the top end of that range all year round will have their metabolic rate in permanent overdrive, so they will die considerably youngster than their expected 8 year lifespan, 5 years sadly is a good age for this temperate fish in a tropical setup.