Definitions of Nano, Pico, and Femto tanks?

[ichthyogeek]

What's the general word on the definitions for Nano, Pico, and Femto tanks? I always figured Nano tanks were anything less than 10/20 gallons, and Pico anything less than1 gallon. And do those apply to the entire system? Is a 2.5 gallon tank attached to a 55 gallon sump considered a pico tank?

 

[xxkenny90xx]

Good question! I call my 4 gallon a pico but now you have me doubting myself! And I've never heard of a femto... Following

 

[samnaz]

Nano - under 40 gallons
Pico - under 4 gallons
Femto ..... never heard of it.

 

[samnaz]

Is a 2.5 gallon tank attached to a 55 gallon sump considered a pico tank?

Yes. Pico tank specifically describes the tank, not the system size. IMO.