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Re: Stock levels and macros
T. Mathews Jr. wrote:
> Hello all,
> Like the originator of this thread, I am also a newbie.
> What is considered 'low', 'moderate' or 'high' fish stocking
> levels in a planted tank? Is it possible to state some rule of
> thumb like "x inches of fish per gallon is low" etc?
Anything near the carrying capacity of the tank is a "high" stocking
I think the carrying capacity is often estimated at 1 inch of fish per
gallon of water, but the real carrying capacity is often higher than
that because of good filtration, aeration and -- in a healthy planted
tank -- plant effects. It varies a lot with the kind of fish; 10 1-inch
guppies in a 10-gallon tank isn't a particularly high load. Two 5-inch
Convicts in a 10-gallon tank is a major overload. It varies with
feeding. Young discus fed a diet of beef heart can quickly overload a
tank, but an equal-sized family of American Flag fish that graze on
algae and only get supplimental feedings won't overload the same tank.
It also varies with the character of the fish. A breeding pair of jewel
cichlids plus any other fish in a medium-sized tank is an automatic
overload. In that case, size makes no difference.
A "low" stocking level in a planted tank is a little more difficult to
define. Fish in a mixed community at low stocking levels rarely interact
with any other fish except the conspecifics that they hang out with.
They don't have to swerve around each other or dart out of one-another's
way, there are few arguments over territory and the sides of the tank
don't severely alter the fish's behavior. Feeding time might be the
only time that you see the fish in a heavily planted tank with a low
To put that on an "inch per gallon" level, maybe something less than 1
inch of fish per 5 gallons would be a low stocking level. Of course,
that's subject to all the variations mentioned before.
A "moderate" fish load would be somewhere in between. The fish have
plenty of freedom to move about naturally, but they may sometimes have
to avoid non-conspecifics. There are some territorial squabbles but
those are usually brief. As a point of reference, I think most of the
tanks pictured in Amano's first book support fish populations that are
on the low side of moderate.