The fantastic answers to my previous question Subgroups of $SL_2(\mathbb R)$ which contain $SL_2(\mathbb Z)$ as a finite index subgroup led me to the following question.

Let $O_K$ be the ring of integers of $K= \mathbb{Q}(\sqrt{p})$, where $p$ is a prime number.

What are the subgroups $\Gamma \subset \mathrm{Sp}(2g,O_K)$ of infinite index which contain $\mathrm{Sp}(2g,\mathbb Z)$? Are there any?