As people have already mentioned, I would highly recommend you not using any (terrestrial) fertilizer that uses ammonical nitrogen (urea) as its nitrogen source, since it will become ammonia in your aquarium (at a pH of 8.6, there will essentially be no ammonium anion formation).
There have been people that have successfully dosed with urea, but I do not think they ever dosed when there was livestock in the aquarium.
i dose urea and NH4 with german blue rams in the tank, they also bread many times in the same tank. plant also grew better with urea and nitrate combination.
Ultilmate fertilizer for faster plant growth