Fish Capacity with External Filter

[KerriPaul]

I have read various posts here about overstocking. I'm not going to go into the details,but if I did some would say that my tank is grossly overstocked.

However the fish are happy, healthy, breeding regularily and some of them (Cardinals Tetras ,Swordtails and Danios) are over two years old.

I do have/do the following:

1) Eheim external filter rated for a much bigger tank than I've got with the large inlet/outlet

2) Contents of filter are sponge x2, large surface bacterial filter material, activated carbon with cotton wool changed monthly

3)A Bar airstone

4)VERY dense planting with home made Co2.

5)100% rainwater with approx 20% change every week

6)Plant food sachet.

7)Frozen food three times a week.

The tank is in my extension where it gets a large amount of sunlight. Since I had the dense plants with Co2 algal growth is virtually zero.

What is the 'statistical' increase in a tank capacity with a large airstone, external filter and dense planting?

 

[enchanted]

Stocking is not just what the tank can handle Biologically, but also giving the fish room to live.

If you would say you are "grossly" overstocked I would not add anymore fish. Not because your filteration wouldn't be able to handle it, but because it takes away from the fish living room and can lead to agressiveness and other undesirable traits coming out.

 

[KerriPaul]

I personnally think that the balance is about right, but having read some of the posts saying that peoples tanks are overstocked after they listed their fish I began to wonder.

I have 2 swordtails, 2 cardinal tetras and a large shoal of about 60 (brachy) danios, nearly all the very small species like D. Nigrofasciatus (max length 2cm) All seem quite happy with no sign of aggression - other than when they are breeding

Ah well I suppose the answer is that it all depends on the species and tank conditions.

 

[dothedew]

What size tank? Tetras like to be in a school of 5 or more.

 

[blue_ram]

My aquarium is quite overstocked as well, but densely planted aquarium will support much greater number of fish while keeping the water clean. Despite the overcrowding, the fish seems to be much happier and active in planted aquarium. But I'm not sure if this applies to larger fish.

The only down side to densely planted aquarium is that, if the plants die, you pretty much lose your bio-filter. Things gets worse, as the plants die and release nitrogen back into the water in the form of ammonia.

 

[benz_020]

that aint over stocked

i had a 40 gal tank with 147 cichlid's and 2 plecos!!!
thoes fish really liked to have fun
couldnt get rid of them fast enough.

 

[dothedew]

Just because your's was horribly overstocked doesn't mean his isn't .