What Is The Max Amount Of Fish I Can Put In This Tank...

[Lola&Spike]

I want to have my 47 gal tank be all tetras, as I feel that is easier for me to not worry about fish attacking one another. How may tetras could I fit in that one tank? They are schooling fish, but also quite small... is my limit really only 47 fish? Or could I fit more?

 

[gpsoph]

What type of tetras are they?

 

[WeslinCamden]

For most common tetras, I would say refrain from putting over 30 total tetra. And while you can do a schooling fish only tank, I really prefer to have at least one slightly aggressive fish. I have 16 rummynose tetras (By far my favorite) and 3 pearl gouramis in my 29 gallon planted tank and its probably the most peaceful and active tank i've ever had. I typically find if you have a bigger fish in the same tank as tetras, it makes them school even tighter.

 

[fishncan]

An old maxim in fishkeeping was 1 inch of fish for every gallon of water but my belief is that is still on the high side. Bear in mind, your 47 gallon tank does not hold 47 gallons of water if your lake is scaped

 

[Byron]

The already-asked question of which tetras is the key.  In a given tank for example, you could keep fewer zebra danio (I know, not a tetra, just for illustration) than you could cardinal tetra, yet both are roughly the same mass.  The traits and needs of the various species is the determining factor.  But there are also the water parameters, aquascaping, live plants; all of these factor in.
 
Which means that the answer to your original question could be as few as 20 in one case, or as many as 80 in another.
 
Byron.