When is a tank overstocked?

[wiEngineer]

This is a more philisophical question than an exact science question, but how do you know when your tank is overstocked?

I know the old "1 inch per gallon" adage (for freshwater tanks), but that has to vary based on the type of fish you have living; ie a 15" pleco is a lot more fish than 15 1-inch tetras.

So, putting aside the hard fast book rules, how do YOU tell when you're overstocked?

[slipknottin]

there are different ways to be "overstocked"

the bio-load is too high
the fish are fighting too much
the fish are very active and their isnt enough swimming room

or in the case of large fish such as sharks (marine fish i know) when it doesnt have enough room to turn around


For my African tanks- it was when there was too much fighting, i started seperating species and individual fish to get stop some of the aggression

for tanks with large active fish- I want a tank thats 2x as deep as the fish, and at least 4-5x its length.

[Serrateeth_2002]

I knoew my tank is overstocked but the fishes are fine,i guess it is in the middle.

[Archer]

When nitrates are still consistently high
despite weekly water changes,
filter media cleanings
and light feedings,
even in a planted tank.