Sadly S denisonii will get too large/too boisterous for this tank (size) but lively while you can keep them 😎
Thank you Alto. This was a concern for me too, but they are slow growers. Knowing the fact I change my setups at least once a year, these will not outgrow my tank. Or, if they will, I can always swap them in LFS for smaller size (current size is about 3cm, youngsters)