Lost all the fish in a 24 gallon aquarium. Lightly stocked 1 bristlenose, 3 panda garra. Well established, fairy heavily planted aquarium used to keep plants and extra white clouds brought in from outside in the fall. Water parameters unchanged, zero to very low nitrates, no ammonia. Temperature steady at about 74. Checked for stray current within aquarium and found none. Pleco hides all day so was unable to notice any change in behavior. Panda garra while looking good appeared to be lethargic and not interested in food for roughly the past week. No obvious signs of disease on the bodies of either species. Food they get is relatively fresh and the same stuff other tanks get without issue. Also cherry shrimp in the tank that appear to be unaffected. Any ideas would be appreciated.