I went back and took a closer look at your Fh's belly. In some pictures there is a noticeable stomach bulge. It could be indicative of constipation. Bug Bites fish food does list peas as one of their ingredients, and peas are a laxative/ stomach tonic. I don't what percentage of pea your fish is receiving in a pinch of food. Frozen pea--thawed, skin pealed, chopped into very small pieces. Sometimes people won't feed their fish for a day to get them to eat the pea, and to cleanse the fish's digestive system. Try instead Also add some > aquarium< salt. 1 tablespoon per 5 gallons= 1 cup minus 1 tablespoon dissolved in tank water or water change water for the amount of water in your sized tank. Note: as you probably know do not add salt directly to water, completely dissolve in water outside of tank before adding to aquarium. I will include some in your gift shipmnt.
You had also mentioned stringy poop. Thin threads could be a sign of worms or Hexamita. Treat with Metronidazole. There are broad spectrum antibiotics, stick with a known company. I would ascertain that that is actually the cause before treatment with antibiotics, as these could compromise or eliminate your beneficial bacteria cultures.
Since you are in college, you might take advantage of the facility and see if you have an ithyologist or ithyology extension department to consult with photos and possibly stool samples (fresh or frozen required?) for analysis to be sure. I have included here a PDF. While I know you have much other studying in school; I find any material relating to my fish highly interesting reading. PDF is: Hexamita In Ornamental Cichlids-eXtension. This article originates from The University of Florida.
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