Sorry for thread skimming so i dont know if your still talking about worms or if this has been mentioned.
I battled these worms for months try every product recomended and none worked. Then i was told about levamosil (spelling) i got a product called levaside and it is a god send. Its a sheep...
I wouldnt risk it.if your keyholes start to breed and start a fight with the convict the convict could very easily kill the keyholes. Convicts are great fish and the best parents ive seen but stocking should really be selected to fit around the convicts. Mine hold their ground with a 12" flowerhorn.
Theres
12 angelfish
4 nanacara thomsi
2 blue acaras
2 unidentified acaras
2 kribs
1 platy
2 bns
6 wild skunk corys
6 wild panda corys
6 peppered corys.
As i said, very overstocked but as long as theres no aggression and the the filters handle the bioload im going to leave it as is.