I'm very sorry to hear the bad news. Cichlids are always hard to lose since they actually have personality! For future reference, though, erythromycin (Maracyn I by Mardel or EM Tabs by API) would have been a considerably better choice. Tetracycline is broad spectrum, but pop eye is almost always gram positive, which erythromycin is more specific for. Also, tetracycline degrades rapidly with exposure to light, actually making it MORE toxic. Metronidazole and Maracyn Two (minocycline) are virtually useless against pop eye, and using the combination at once will do little butbquickly destroy the fish's liver and kidneys. please just keep all this in mind in case you see any future symptoms...