There are some members who use Oscomote, or did anyway, but it is not recommended. First, this product is aimed at terrestrial plants, not aquatic, and the nitrates and phosphorus is higher than necessary, which frequently cause algae problems and obviously high nitrates. And as nitrate is detrimental to fish, keeping nitrates as low as possible is advisable.
The Seachem's Flourish Tabs are what I have used for the past 8+ years. They do not have these detriments, plus they do not get into the water column at all, so even better at algae control and fish health.