Overstocked tank/water test results

[RRiley774]

Just curious, if you tank is overstocked what would your water test results look like from day to day?

Another words, if your tank is cycled and your results are good consistantly then you add one more fish over stocking the recommended capacity what would your water tests look like in an already cycled tank?

 

[Keke89]

I am very interested as well...

 

[DeirdreHoyle]

I would guess you would have increased ammonia levels and maybe a lower pH level but I'm not totally sure. I'm curious as well.

 

[Camescu]

I reckon it the water quality would mostly be down to filter capacity and whether it could handle the bioload.

But overstocking would have other issues besides water quality. Fish could feel stressed, fewer hiding spaces and less swim room without bumping into someone else.... That sort of thing. That's how I see it anyway.

 

[BillD]

Assuming sufficient filtration, the only change might be a rise in nitrates at a slightly higher rate than normal. Malawi tanks (typically all male) are often heavily stocked to avoid aggression. Less aggression means less stress.A higher rate of increase in the nitrate level would mean bigger or more frequent water changes, or, perhaps, even both.


The tank above is in a fish lab at a zoo. The fish are, if I remember correctly, Oreochrmis esculentus. They are part of a species preservation program. Clearly, the tank is heavily stocked. The water conditions are excellent because it is well maintained.

 

[Cynic]

There are a number of issues with overstocking but strictly chemical wise the main issue is the added ammonia the fish create. Now as we all know ammonia can be cycled into nitrAte so the most common chemical sign of an overstocked tank is high nitrAtes 40+ as well as extreme difficulty reducing them (Which is why overstocked tanks need frequent water changes).

However if your tank is so overstocked and there isn't sufficient space for bacterial colonization then it won't cycle at all and ammonia will remain present.

In addition, but I'm a bit hazy on this, an overstocked tank uses far more of the water's minerals than normal so it is not unusual for the water hardness to crash and a PH crash to follow.

It's not as simple as overstocking equals more water changes though. You need to consider space issues for both territorial natures and swimming size.

 

[Delapool]

Yes, I'd have thought kh would decrease faster. I guess water clarity would eventually suffer as well? Makes sense nitrates would increase faster and probably the bio filter would pick up the extra load for ammonia and nitrite.