ForeverCatch

Predicting forever chemical (PFAS) contamination in your catch

Disclaimer This tool is for research purposes only. It uses a predictive model that may have significant margins of error. It is not an official health advisory. Always refer to your local Department of Fish and Wildlife for official consumption guidelines.

Check a Fish See How It Works

Built on 1,110 EPA composite samples (each made from 3 to 5 fish) covering 48 species.

Check Your Fish

Pick where it was caught
Choose the species and water type
Enter its length

Catch location Click the map where the fish was caught, or type coordinates below.

United States only. The model is built on U.S. EPA fish data and U.S. military base and Census urban-area records, so it only works for fish caught in the U.S.

Latitude Decimal degrees, -90 to 90

Longitude Decimal degrees, -180 to 180

Fish Species Species of the fish that was caught

Fish Length (inches) Total length of the fish, in inches

Type of Water The kind of water body the fish came from

The location is sent to the Open-Meteo elevation and U.S. Census TIGERweb services, and your inputs go to our prediction server. We only keep anonymous counts of visits and predictions, never your inputs or anything that identifies you.

Prediction Results

Estimated PFAS concentration for this catch:

Exact prediction

Warning: can be highly variable. Don't treat it as fact.

95% upper bound

<--

99% upper bound

<--

How to read these numbers

Exact prediction is our single best estimate, from an Extra Trees machine-learning model with a median error of 3.04 ppb. Individual fish can still be much higher or lower.
Upper bounds are the levels we are 95% and 99% confident the PFAS in this fish falls below.

Deciding whether to eat it? Use the 95% upper bound, not the exact prediction, which can be far off. The bound is cautious on purpose. Compare it with the chart below and check your state's fish advisories.

How often can you eat it?

This chart is from the Great Lakes Consortium for Fish Consumption Advisories (2025). It shows how often it's OK to eat a fish based on how much PFOS is in its meat.

PFOS is one type of PFAS, and it's the main one found in fish. In a study of freshwater fish across the U.S., PFOS made up about 74% of the total PFAS on average.

PFOS in the fish (ppb)	How often you can eat it
0 to 2.5	4 or more meals a week
Over 2.5 to 5	2 meals a week
Over 5 to 10	1 meal a week
Over 10 to 40	1 meal a month
Over 40	Do not eat

Our estimates above count all PFAS together, not just PFOS, so the PFOS in your fish is usually a bit lower than our number. For a cautious read, compare the chart with the 95% upper bound above, not the exact prediction. Sources: Best Practice for PFOS Guidelines, Table 1 (September 2025); Barbo et al., Environmental Research (2023).

Nearest Military Base

Nearest Urban Area

Elevation

Check another fish How is this calculated?