Gil the Reactive Fish Sculpture

Gil the Reactive Fish Sculpture

at The New Canal Lighthouse

photo: Patrick Niddrie

The Environmental Protection Agency's (EPA) Reactive Fish Sculpture translates water sensor measurements from the United States Geological Survey (USGS) National Water Information System (NWIS) to colors and motion. The sculpture, designed and constructed by EPA, is located at the New Canal Lighthouse and uses electronics and LED lights to move and change color, indicating changes in the water quality data. For example, the height of the sculpture changes relative to turbidity, the speed at which the tail moves reflects dissolved oxygen, the color of the fish represents salinity concentrations, and the color of the base corresponds to algae concentrations.

Gil's colors and motion will reflect measurements from two different sensor sites, one on Lake Pontchartrain and the other on the Mississippi River in Baton Rouge. EPA and USGS installed water sensors next to the New Canal Lighthouse as a part of EPA's Village Blue project in February 2021.


Real-time water quality monitoring helps communities better understand Lake Pontchartrain
water quality and its connection to the Mississippi River.


Lake Pontchartrain has a low salinity level, measuring around 1.6 parts per thousand (PPT). When Gil is displaying measurements from the lake his ribcage will typically be purple. Mississippi River water has a low salt concentration and has very low salinity. When Gil displays measurements from the river his ribcage will typically be gold.



Low salinity
Less than 0.2 parts per thousand (PPT)


Medium salinity
Greater than 0.2 PPT, less than 0.5 PPT


High salinity
Greater than 0.5 PPT

Dissolved Oxygen

Gil's tail will move with a lower range of motion and a longer pause for low levels of dissolved oxygen. Medium levels of dissolved oxygen cause an increased range of motion of the tail with a shorter pause, and high levels of dissolved oxygen result in an increased range of motion of the tail with a similar pause. Gil's eyes also blink one, two, or three times in demo mode to show the tail motion level.


Gil's tail movement above reflects high dissolved oxygen readings (greater than 9.40 mg/L).


Algae contains chlorophyll. Chlorophyll levels measured in the lake change Gil's base color. Lake Pontchartrain typically has low concentrations of algae but increases in nutrient concentrations may lead to an algal bloom. Mississippi River water has a high nutrient content, but sensor data is not available for algae in the river, so Gil’s base will always appear blue when displaying data from the Mississippi River.



Low algae
Less than 3.75 chlorophyll fluorescence (FChl)


Medium algae
Greater than 3.75 FChl, less than 11.25 FChl


High algae
Greater than 11.25 FCHl


Gil will rise or lower based on turbidity measurements. Lake Pontchartrain typically has low turbidity, but wave action increases the amount of sand and lake-bottom material, which can dramatically increase turbidity levels in the lake. Mississippi River water has high turbidity levels due to sand, silt and clay particles carried by the current.



Low turbidity
Less than 8.93 Formazin Nephelometric Units (FNU)


Greater than 8.93 FNU, less than 41.30 FNU


High turbidity
Greater than 41.30 FNU

What Water Quality Parameters is Gil Reflecting?

Based on Gil pictured to the right, what are the water quality parameter measurements?
parts per thousand (PPT)
chlorophyll fluorescence (FChl)
Dissolved Oxygen
milligrams per liter (mg/L)
formazin nephelometric units (FNU)


EPA's Reactive Fish Sculpture is a demonstration project funded by EPA's Office of Research and Development, EPA Region 6, EPA Region 4's Gulf of Mexico Division, and the Environmental Modeling and Visualization Center.


Find Gil at The New Canal Lighthouse!

Open 10:00am - 4:00pm, Tuesday - Saturday