How to Use Chlorofishy

Getting Started

Sign in with your Google account or enter your email to receive a magic link. Email users can set a password so you don't have to check your inbox every time. Agree to the Terms of Service (one-time), and you're on the map. The latest sea surface temperature data loads automatically.

Don't want to sign in? You can explore the map as a guest. See what's free and what's paid for exactly what a guest, a free account, and a Pro plan each see.

Passes vs. Composites

Every layer on the map comes in two forms: a raw satellite pass (one overpass, real holes, usually a few hours old) and a daily composite that blends multiple sensors and fills the gaps, usually a day or two old. See passes vs. composites for which to trust when.

Reading the Map

Click or tap anywhere on the colored ocean for an exact reading: SST in °C and °F, chlorophyll in mg/m³ plus an estimated water visibility. See reading the map for how the readout works and why it's instant.

Why There Are Holes

Transparent patches on a satellite pass are real coverage gaps, not a bug: the satellite genuinely couldn't get a reading there. See why there are holes for what causes them and how the map labels them.

Using the Timeline

The row of pills near the bottom of the screen steps through every available pass and composite for the current region. See using the timeline for how the ordering works, what the icons mean, and how long data sticks around.

Reading the Legend

The color scale bar above the timeline means something different for SST than it does for chlorophyll, and it doesn't always mean the same thing twice even on the same layer. See reading the legend before you compare colors across two different views.

Map Controls

Layer toolbar. The SST / Chloro toggle and the source dropdown sit in the top-right on mobile, top-center on desktop. The dropdown lets you pick All Composites, All Satellites, or an individual satellite for the active region.

Map overlays menu. The layers icon at the right end of the toolbar opens a panel with toggles for Buoys and Alerts, each showing how many are currently in view.

Account menu. Tap your avatar (or the menu icon as a guest) to open the drawer: temperature units (°F/°C), default layer and region, a "Copy share link" that captures your current view, data source provenance, alert management, and billing.

Finding Temperature Breaks

Pin a point, step through passes with the arrow keys, and watch a break build or dissolve: the single highest-value workflow on the map. See finding temperature breaks for the full workflow, or our temperature breaks page for why breaks matter in the first place.

Regions

Chlorofishy divides the world's fishing waters into 41 regions. Click or tap a region outline on the map to switch to it: there's no dropdown, the map itself is the region picker. See setting a default source and region for exactly what switching does and how defaults work, or /regions/socal for an example of a region's own fishing guide page.

Buoys

Toggle Buoys on from the Map overlays menu to see NDBC weather buoy stations as dots on the map, tinted by water temperature. See reading buoy data for what the tint means, freshness states, and history charts. Buoys require a Pro subscription for the region(s) on your plan.

Depth Contours

Turn on Depth Contours in the overlay menu to draw the seafloor under the satellite layers: contour lines, charted soundings, and a depth reading when you tap the map. Available to everyone, including guests.

Unlike SST and chlorophyll, this layer is static: the seafloor doesn't change on a satellite's schedule, so it's built once per region rather than refreshed. Detail comes from the finest source that can honestly support it: survey multibeam where it exists, NOAA chart data inshore where it doesn't, and a global compilation beyond that. Lines get finer as you zoom in, because a contour drawn closer together than the underlying data can support would be inventing detail.

Tapping the map gives one depth. A ~ means it was estimated between contours; a number without one is a charted sounding, an actual measurement at that spot. The reading also names which source it came from.

Depth contours, soundings, and depth readouts are provided for fishing and dive planning only and are not for navigation. They are derived from public bathymetric datasets that vary in age, accuracy, and coverage, and may not reflect current conditions. Never rely on this product for safe passage, anchoring, or collision avoidance; always use official nautical charts and your own soundings.

Regions ship in waves, so the toggle only appears where an archive exists. Full source and licence details are on the data sources page.

Alerts

Get notified by email when conditions in an area you care about match what you're looking for: a temperature break forming, a chlorophyll edge moving in. See setting up an alert for how to draw one, and alert conditions and logic for how AND/OR and cooldowns actually behave. Alerts require a Pro subscription for the region the alert is drawn in.

Compare Mode (Dual Map)

Compare mode lets you view two maps side by side, with a synced camera and region but independent layers per pane. See using compare mode for what syncs and what doesn't, and timeline lock for coupling the two timelines together.

Zoom and Resolution

Each dataset has a native resolution, and zooming past it just stretches the same data without adding detail. SST composites are ~1km. Chlorophyll composites are ~4km (~8km once you account for the Sentinel-3 contribution to that blend). Satellite passes vary by satellite: from ~750m (VIIRS chlorophyll) up to ~25km (AMSR2 microwave SST). The current source is shown in the toolbar dropdown.

If zooming in stops revealing more detail, you've hit the native resolution limit. That's the actual data, not a limitation of the map.

Data Provenance

Open the account menu → Data sources → "View provenance" to see exactly:

• What sensor and satellite captured the data
• The native resolution (e.g. ~1km)
• When the data was captured and when we ingested it
• Whether it's a composite (gap-filled) or a real satellite pass (gaps are genuine)

Transparency is the core principle. You should always be able to answer: "Where did this data come from and how fresh is it?" See also our data sources page for the full breakdown by sensor.

What Is Free and What Is Paid

Guest, free account, paid-in-region, and paid-out-of-region each see something different. See what's free and what's paid for the exact breakdown, or pricing for plan rates.

Managing your subscription. See managing your subscription to update payment details, change plans, or cancel, and swapping your region to change coverage without contacting support.

Keyboard Shortcuts (Desktop)

Left and right arrow keys step through passes, skipping dead and locked ones, and Escape closes whatever panel is open. See keyboard shortcuts for the complete list and what each one does and doesn't close.

FAQ

How often does data update?

The pipeline checks for new data every 10 minutes. Satellites make multiple passes per day (the exact number depends on the region and orbit), so you'll typically see several new passes appear throughout the day. Composites update once daily.

How do I cancel or change my plan?

Open the account menu → Billing → "Manage subscription" to reach Stripe's billing portal, where you can update payment details, change plans, or cancel.

Can I use this for navigation or safety decisions?

No. Chlorofishy is for informational purposes only. Do not rely on this data for navigation, safety, or any purpose where inaccurate data could cause harm. Always use official charts and follow maritime safety protocols.

Questions or Feedback?

Email us at [email protected]. We'd love to hear how you're using the platform.