Yes, most newts can be sold, try Caudata.org
California newts (Taricha torosa) are not endangered. However, California Tiger Salamanders (Ambystoma californiense) are endangered.
Newts are Ectothermic
Yes, newts have toxins in their skin ranging from being an irritant to deadly to humans. Taricha torosa (California Newt) and Taricha granulosa (Rough Skinned Newt) are very toxic. Ingesting any of the toxins will kill a healthy adult.
newts are ectothermic
all newts are carnivores
you can buy eye of newts from the mage shop for 3gp in port sarim and sell them in the grand exchange for around 70gp :)
it is not telling me what i want
newts can stay together
Newts have toxic skin, and feathery gills.
yes, bids do eat newts
No. Salamnders and newts are two different species.
Newts reproduce during the winter.