hello Nico and welcome. :)
could you let us know a few more things please........
how long has your tank been set up for.
who is in there with him.
what temperature is the tank.
what dechlorinator do you use on water change day.
how often do you preform water changes
what size is the tank.
any bog wood in the tank.
any carbon in the filter.
what exactly are the water results for Amonia,nitrAte,nitrIte.
i know lots of questions,however,please if you can answer them,it may give us a clue
as to why you are also having trouble.
where abouts are you(if you don't mind me asking)
i don't think i've seen a baloon ram befor,i'll have to do a google.........
oh yeah also what food,as Pasfur rightly mentioned.