The digitate hydroids in my 13.5g tank seem almost impossible to get rid of i sometimes try and remove them with turkey blaster but unless i get the whole body the foot they grow back their head. my fire shrimp always gets annoyed when hes walking and jumps almost everytime he touches one, my emerald crab doesnt seem to get annoyed by them cause they touch her and she doesnt react. same with all my hermits.