# Ghost Knives and Bala sharks



## Snefru (Mar 1, 2009)

Before I started with live plants, I always had a ghost knife and Balas. I had one bala for 5 years and my first ghost for 6 years. Ever since I started with my planted aquarium, I have been unable to keep them. I have a 55g with 140 watts of lighting. The rest of the bio load are tetras, ottos, cory cats. I inject CO2 and fert 1/8 tsp Mono Potassium Phosphate and CSM+B every other day. I dose excel (Cydex) daily. All parameters are within normal ranges. Is this just my trade off for plants? Any help would be appreciated.


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## CL0NE1 (Jul 27, 2011)

Wouldn't the size of a ghost knife far exceed the recommended size for a 55 gal? I mean, I don't know how fast they grow, I just know they get big....like 20" big.

Don't ghost knife fish require high oxygen levels? If so...you are adding CO2, which reduces oxygen levels making it more difficult for them to get enough oxygen. If they can't get enough oxygen, they will be too fatigued to eat or take care of themselves and eventually die.

Perhaps decreasing the CO2 addition and adding a device to create a current going through the hole that it hides in.

It is also quite possible that some of the chemicals you are using are causing problems.

Ghost knife fish are found in fast moving rivers and streams. This usually means they need high oxygen levels and rather clean water to be healthy.


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## m00se (Jan 18, 2011)

The presence of CO2 does not alter O2 levels. It does alter the pH of the water.


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## Skizhx (Oct 12, 2010)

I'm probably wrong cause it's been awhile since I've done chemistry or biology, but isn't the dissolved and atmospheric CO2 and O2 at equillibrium? So by forcefully raising the dissolved CO2 levels, the dissolved O2 will diffuse into the atmosphere to maintain the balanced equilibrium?

Would look something like

CO2(aq) + O2(aq) <---> CO2(g) + O2(g)

Lol, sorry I'm probably pretty off on this. It bugs me when I forget science that I used to know pretty well -_-


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## DishyFishy (Aug 11, 2011)

I was under the impression that too much CO2 can indeed suck out the oxygen in the tank.. that's why when you accidentally gas your tank you see fish gasping at the top


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## m00se (Jan 18, 2011)

Well, no. While the presence of CO2 in excess will impede the ability of the blood to uptake oxygen in fish, it does not mean that CO2 reduces the O2 in the water.

It has to do with, among other things, the acid/base equilibrium of the blood.

Water is able to have both dissolved and coexisting quite nicely.


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## m00se (Jan 18, 2011)

Skizhx said:


> I'm probably wrong cause it's been awhile since I've done chemistry or biology, but isn't the dissolved and atmospheric CO2 and O2 at equillibrium? So by forcefully raising the dissolved CO2 levels, the dissolved O2 will diffuse into the atmosphere to maintain the balanced equilibrium?


The equilibrium of O2 and CO2 to atmosphere are independent of each other. Neither at STP have anywhere near their saturation potential in H2O.

[smilie=b:


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## DishyFishy (Aug 11, 2011)

m00se said:


> Well, no. While the presence of CO2 in excess will impede the ability of the blood to uptake oxygen in fish, it does not mean that CO2 reduces the O2 in the water.
> 
> It has to do with, among other things, the acid/base equilibrium of the blood.
> 
> Water is able to have both dissolved and coexisting quite nicely.


Very interesting, and I learned something new! Thanks.


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## CL0NE1 (Jul 27, 2011)

Well, whether it is a lower level of O2 or that the fish can't utilize O2 as a result of elevated CO2 levels, I would still suggest: lowering the CO2 levels, creating a current going through the hole in which it hides, and decreasing the amount of chemicals you add to your tank(because it likes more pure water). If it doesn't work, maybe it is another environmental setting in your tank.


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