Dont bother with neither.
Dont expose or use med where med may not work when really needed since organism can evolved to develop resistance.
Look into simple
spirulina flakes. that Aquarian (I find them poor quality) maybe made for either carnivore or
omnivore where
mbuna are more vegetarian.
I do know bloat can be associated to poor water quality. I dont know if it is related to eating too much planaria.
If you really think it is planaria, you can scoop out all the gravel and replace with new or leave it
bare bottom for now. Do not touch/replace filter when doing this.
Keep the water in check. What is your
pH? I am not asking for others with an assumption that is well monitored.
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i hope it is not something serious as I think this is very interesting and beautiful fish as I can not recall what it may be. I prefer the old coloration than newer coloration, personally.