Misfolding and aggregation of proteins has been implicated in a number of diseases such as Alzheimer's, Huntington's, and mad cow disease. Misfolded forms of the thyroxine transport protein transthyretin lead to familial systemic amyloidosis which is estimated to afflict up to 20% of the population over the age of 80. An accurate understanding of the solution conditions that promote and prevent aggregation could allow for design of accelerated diagnostics and improved therapeutic approaches for these diseases. We have previously shown that the deactivation kinetics of proteins in chaotropic salt solutions show a strong dependence on salt ion hydration. Here we observe the aggregation of the amyloid fibril-forming protein transthyretin in salt solutions to test the utility of ion hydration as a predictor of amyloid fibril formation rates.