Fish in tanks can easily die from high concentration of nitrate and nitrites in water. Water quality testing can be costly and time consuming. By designing a plasmid that combines the PyeaR promoter, a ribosome binding site and the tspurple gene. This plasmid would be used to transform E.coli that is housed in a chamber that would hang off the side of the fish tank. This would be called “NitriAlert”. There will be a visual color change in the device bringing attention to the excessive amount of nitrate/nitrites in the tank allowing for a water change before the fish are killed. By adding “NitriAlert” into the tank less fish will be harmed by a sudden spike of nitrate/nitrite.