I only worry because I did a wate change a couple of weeks ago and filled the tank a little to much. So much as to stop surface aggitation being that the water was to the underside of the top.... I got up the next morning and had all the africans in the 180g glass tank gasping for air and I ended up losing a female venustus from my colony and I had to run ton stones for half of that day before the rest of the crew were acting normal and breathing normal again.... the tank inhabitants are listed above and I do weekly and bi-weekly water changes (135g, 40g and 15g get b/w w/c's)...
What are you using for filtration?