Keeping money in a fixed deposit is not permissible. And if someone kept it out of ignorance, then it is necessary to spend the interest money in its prescribed avenues. There are two unanimously agreed-upon avenues for it:
(1) Non-obligatory (unjustified) taxes. (2) Poor Muslims.
Interest money cannot be given in payment of interest.
It is better to act upon the unanimously agreed-upon opinion. In times of severe need, if the disputed opinion is acted upon, then in any case, there is scope for it. (Habib al-Fatawa Vol: 7 / Pg: 172)