I have a 150 were I lost two ripe fish and a dojo in two days I'm a bit angry seeing as my ripe and dojo are my favorite fish. I took ever thing out decorations and all left pleco and last rope in there he acting a bit weird to water test show perfect. My gf said when the one rope died he had white around his mouth. I did a 75 percent water change afet that and j just don't understand is it a disease I used medication in there nothing happened please help.