Q.
What is the pH level in water needed for
rainbow trout to survive? Can rainbow
trout survive in an acidic environment?
A.
Although you are asking specifically about
rainbow trout, it will be easier if I respond
for trout, in general, and add any specific
information about rainbows.
Trout generally prefer pH levels between 6
and 9, with 7, of course, being neutral and
acidic conditions below 7 and basic conditions
above 7. Thus, obviously, they prefer pH
conditions around neutral but slightly more
on the basic side.
As for survival under acidic conditions, it
depends on the species and the softness of
the water; trout are more sensitive to acidic
conditions in soft water than they are in
hard waters containing higher concentrations
of calcium and magnesium carbonates. Anyway,
direct toxic effects on adult salmonids has
been observed at pH levels between 5.5 and
4.5, and rainbow trout appear to be more
sensitive than other species to acid stress.
Brook trout are more tolerant than other
trouts.
If you have a question, please feel free to contact me.
~ C. E. (Bert) Cushing, aka Streamdoctor
105 W. Cherokee Dr.
Estes Park, CO 80517
Phone: 970-577-1584
Email: streamdoctor@aol.com
The ‘Stream Doctor’ is a retired professional stream ecologist and
author, now living in the West and spending way too much time
fly-fishing. You are invited to submit questions relating to
anything stream related directly to him for use in this Q & A Feature
at streamdoctor@aol.com.
Originally published December 13th, 2004 on Fly Anglers Online by Robert Younghanz.