The 3 black skirt tetras, and 3 cory cats I have left, I would like to put in my 10 gallon from the 20 and in a week add 3 more black skirts. This tank is empty newly cycled and pretty. I think it will show up the tetras . My real question is, originally the tank was at 78 but when they got sick I upped the temp to 80. They seem to like this temp, and was wondering if I should up the 10 gallon to 80, or should I leave it at 78. My feeling is they are in temp of 80 and now maybe 78 would be too cold. What do you think? I want to do the right thing. Thanks