Marcus Fox wrote in message
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"Jim Brown" wrote in message
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Marcus Fox wrote in
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"Cplus" wrote in message
e.rogers.com...
The two remaining mollies (had another black one die on me this
morning)
that I had in 20g tank I moved to my daughter's 10 gallon tank
(because
the
20g is high in nitrites still). I moved them because their back fin
(not
sure of the specific name) was starting to curl in (they're lyretail
mollies).


The 10G tank already houses :
1 guppy
2 angels
5 tetras (2 glow light, 3 pristella)
a pleco

and now I've added the mollies. Will that be too big of a load? It
doesn't
seem like it when I write it down but it seems busy in the tank.

I thought a good rule of thumb was one inch of fish per square inch of
surface. And I thought angelfish ate tetras?

Marcus



One fairly common standard (but not fully accurate) is one inch of fish
per
gallon of water. That equates to about one inch of fish for every
twenty
square inches of surface.
Using a standard 15 gallon tank with a surface of 12" x 24", that's 288
square inches, or more than twenty feet of fish using your rule.
Not all angels eat all tetras. A better statement would be almost all
fish
will eat fish small enough to fit in their mouth.

Yes, I was a bit confused when I wrote that. But I find the 1 inch per
gallon rule innacurate, particularly as a 1 inch fish weighs about 1/8th
of
a 2 inch fish of the same shape, so it clearly uses more like 1/8th of the
oxygen and produces a corresponding amount of waste products.

This table should be a bit more accurate, therefore. (It is not mine)

Size No. Per cm2 of surface Approx.
cm2 per fish

1 400
2.5
2 110
9
3 50
20
4 25
40
5 12
80
6 8
125
8 5
200
10 2
500
12 1
750
15 1
1100

HTH

Marcus



You are right in that fish mass has more of an impact than fish length.
Unfortunately, while mass is definitely better but harder to estimate, there
are also factors such as activity, age, aquarium parameters, and types of
food.
Your chart still needs some work. The first column sets out square cm's of
fish but it might be better to set out cubic cm's. The second column sets
out square cm's, and how many one inch fish could be stocked in an aquarium
with a (roughly converted) one inch square surface.
You can try but I don't think anyone will deveope anything better than a
rough guide for 'bread and butter' fish from the LFS. Far better to learn
from the experience of others and add that to one's own observations.

Jim