Given your further observations, I'd just dose for 3 days, & then observe
Increase water change frequency for the next 1-2 weeks (don't drive yourself crazy, just do what you can)
Male ram seems well enough in photos, it's common for good parent fish to concentrate on parenting over eating, you might try dropping some (small amount) brine shrimp or other favourite food in his zone - after distracting the rest of the tank inhabitants (with lots of food) .... brine shrimp, daphnia, calanus are "better" foods when gut issues are suspected
I usually medicate at a time when I can observe tank for an hour or so, just in case of adverse reactions
- large (75% - 90%) water change is quickest way to deal with stress response, then add carbon ... catching & removing fish is usually more stressful - so near end of photoperiod or dim lighting
Tank volume is usually calculated as maximum water that might be held within the space, in most aquariums, actual water volume may be significantly less than this (theoretical) value - medication toxicity is rarely a consideration in fish tanks as the difference between therapeutic & toxic levels is usually very broad (think factors of 5, 10, 20 etc)
Most pet trade home use medications err on the side of extreme caution - I always confirm therapeutic doses (of the active ingredient) for ornamental fish
University of Florida Fish Veterinary department has a series of articles developed for aquaculture, hobbyists
I've included the Fish Disease link but there are many husbandry articles as well
As I mentioned previously, all the "stuff" in aquaria tend to reduce medication levels in the water column, so again overdosing is rare & "generous" dosing is usually required for effective treatment levels.
Most medications are "stressful" to some degree so it's not unusual to note lessened activity/coloration,
though in the case of external parasites, it's common to observe increased activity & general fish "happiness" within an hour of dosing.