Prime can help. It binds the ammonia, creating ammonium, which is non-toxic. Still a short term fix (those ions can be stripped away, returning the ammonium to ammonia, depends on your pH). Polyfilter will also adsorb the ammonia.
Water changed will be best--and I wouldn't go with little ones. 25% won't make a significant difference. I would do a 50% water change, wait a couple hours, then do another one, and repeat until the levels test below 1.