How to Catch Mahi-Mahi in April

The Ultimate Guide to Catching Mahi Mahi

Fishing Marathon, Islamorada and Key Largo in March and April

If you’re looking for the best springtime fishing destinations for catching mahi-mahi, sailfish, and wahoo in the Florida Keys, you can’t go wrong with Islamorada and Key Largo. These two areas are home to some of the most popular fish species in the region, including mahi-mahi, tuna, sailfish, wahoo, snappers, and groupers. Islamorada is particularly well-known for its sailfish, while Key Largo is a prime spot for wahoo. April is an ideal time to fish for mahi-mahi in the Keys, as this is when they are typically migrating through the area.

how to catch Mahi Mahi

March and April are the Florida Keys’ windiest month of the year, but with a bit of preparation and knowledge, you can make the most of this month’s conditions and have a great day out on the water, perhaps an epic day if you get dialed in on “tailing conditions.”

What are Tailing Condtions?

Tailing conditions happen when the wind and current line up just right; the fish will swim on the surface into the current. Then, they surf down the waves with the tips of their tails out of the water. Historically the months of March and April are the best month for this phenomenon to happen.

Predicting Tailing Condtions

Anyone who has ever been fishing knows that there is no surefire formula for predicting success. However, experienced anglers have developed several tricks and techniques that can increase the chances of predicting when tailing conditions can now happen with precision, thanks to technology. One of the most critical factors in fishing is choosing the right time and place. Certain conditions, such as the tides, the weather, and the amount of daylight, can all affect fish behavior. 

Here are some helpful tips and tricks for predicting when and where tailing conditions will happen in the Upper Florida Keys. 

Wind and More of It 

First and foremost, there must be a period of high wind from the Northeast in the Upper Florida Keys. Therefore, it’s essential to understand that high winds usually occur in cycles of several days.

Determine How Far Out the Gulf Stream Current off Key Largo, Islamorada and Marathon Before Going Fishing Offshore

The Gulf Stream is a warm and swift Atlantic ocean current that plays a critical role in shaping the climate and marine environment of the eastern coastline of the United States. It originates in the Gulf of Mexico and follows the eastern coastlines of the United States and Newfoundland before crossing the Atlantic Ocean as the North Atlantic Drift. The Gulf Stream is characterized by its high temperature and salinity, making it a distinct water mass compared to adjacent cooler waters.

How far out is the Gulf Stream Current?  The strong NE wind conditions move the western edge of the gulf stream current close to the reef line in the Upper Florida Keys during the months of March and April.  To locate the true edge of the Gulf Stream current use SATFISH.

Gulf Stream Florida Keys

In locating the western edge of the Gulf Stream, here are some key points that I like to keep in mind while evaluating SATFISH SST Charts.

  • The narrowness and depth of the Gulf Stream, which typically ranges from 50 to 100 kilometers wide and reaches great depths, make it a significant and easily identifiable feature in the ocean. This narrowness results in a strong current with peak speeds that can reach around 5 to 6 mph.

  • Speed variations within the Gulf Stream are also notable. Although it averages around four miles per hour, the speed can fluctuate depending on location and other oceanographic factors. Dolphin tend hang just inside of the fast moving Gulf Stream current, I talk about the secret to finding dolphin here.

  • Western intensification is a phenomenon associated with the Gulf Stream as a western boundary current. This means the current is stronger and deeper on its western side — the side closer to the United States — than it is in the east.

  • The Gulf Stream’s influence extends across the Atlantic, with the eastern edge gradually moving seaward as the current travels northward.

  • The shoreward edge of the Gulf Stream is a valuable piece of information for dolphin fishing in the Florida key, but it is not always readily available. It is influenced by various factors such as winds and can have effects on local weather conditions. SATFISH provides the most accurate information when it comes to finding the shoreward edge of the Gulf Stream.

For those in the Florida Keys sport fishing community, understanding the exact location of the Gulf Stream’s edge is crucial as it can indicate where baitfish may be more abundant due to the convergence of different ecosystems and the availability of food sources brought by the current.

By using SATFISH you get real-time insights into the location and behavior of the Gulf Stream, aiding in navigation and strategic planning for early season dolphin fishing trip[s off the Florida Keys.

You can use the Gulf Stream overlay to track the movement of the gulf stream.

current and check the NOAA marine weather forecast for an approximate position of the gulf stream.

How to Catch Dolphin

When you see that the western edge of Gulf Stream current is within 1-3 miles of either Tennessee Light off Islamorada or Sombrero Light off Marathon, it’s time to go fishing!

Color Edge

Every day, winds from the Northeast push the gulf stream closer to the reef. When the gulf stream gets close to the reef, we get that perfect powder blue color change, setting up for tailing conditions. Sailfish tend to congregate in areas where the water is a powdery blue. This powder blue water color occurs when the gulf stream pushes up against the reef, creating a wind-against-current situation.

Powder Blue Water

This powder blue-colored water is where the “mixology” is happening – where the green water from the Gulf of Mexico/Florida Bay meets the blue gulf stream water, creating a powder blue color. It’s like motor oil and water together; they separate. You are looking for hard color or subtle water color changes.

best mahi mahi fishing tips

The sailfish stand out in the powder blue water, making them easier to spot and hunt along with fish like mahi mahi and wahoo.  So when you’re out on the reef, keep an eye out for those water color changes. Be on the lookout for this color change between depths of 60 out to 450 ft. 

The Secret

Now here is the secret to an epic day. Strong outgoing tides around the full or new moons push that dirty green water from the gulf out to the oceanside where it meets the gulf stream current creating epic tailing conditions. Remember, some moons show brighter than others earlier in the month, so you want to plan accordingly. Refer to my last blog The Best Solar Lunar Secrets Revealed

The Secret to Catching Big Slammer Dolphin Offshore in March and April

The Gulf Stream’s dynamic nature profoundly affects fishing conditions especially during the spring time(March and April), and this is especially true in transitional seasons like spring and fall when surrounding water temperatures can contrast sharply with the warmer waters of the current itself.  Make sure you read the my Ultimate Guide to for catching Dolphin by clicking here.

Here’s how these dynamics play out:

Warm Water Movements: Fingers, backflows, and warm eddies are essentially offshoots of the Gulf Stream that carry its characteristic warm water westward, at times beyond the 600 contour line off the upper Florida Keys. These areas stand out against the cooler waters typically found west of the Gulf Stream during these seasons.

Dolphin Fish Migration: Slammer size dolphin fish and their prey(flying fish) are known to follow the warm Gulf Steam current during the early spring, which offers more comfortable habitats and abundant food sources for big dolphin.  Thus, they often migrate with these fingers and eddies as they extend westward, providing anglers with opportunities to find them outside the main Gulf Stream.

Rip Formation: These springtime rips are surface disturbances created by the convergence of different currents or water masses. They commonly form along the edges of these fingers, backflows, and eddies, marking zones where fish might congregate due to the concentration of baitfish attracted to the area.

Productive Bottom Structures: The presence of good bottom structure—such as wrecks, reefs, and ledges—can enhance the productivity of a fishing spot. When these structures are within the path of warm water movements, they can become hotspots teeming with fish activity due to the structure providing additional habitat benefits. Below is a picture of the Marathon Hump. It is very productive Marathon, Florida fishing spot off the Florida Keys. During the months of March and April this is great spot for catching large slammer dolphin off of Marathon. The best way to find productive bottom is to purchase a Standard Map.standard mapping

Avoiding Cold Water: Just as warm water can be beneficial for fishing, cold water is generally have the opposite effect in the spring for dolphin. Cold water in the spring as is in biological activity and thus less attractive to both baitfish and game fish.

Analyzing the water color through SATFISH chlorophyll charts is highly recommended during the months of March and April  as it helps to locate areas where phytoplankton concentrations are higher, influencing the presence of baitfish and larger predatory fish. The presence of a defined temperature breaks are more defined on the SATFISH sea surface temperature (SST) data and which often aligns with significant shifts in water color. These breaks delineate where warm and cold water masses meet, creating potential zones for weedline formation.

SATFISH Discount for Good Karma Sportfishing Followers

SatFish Offshore offers a 30-day free trial for new users. To use this offer, visit their website and create a free account. You must provide essential information to create your account, such as your name, email address, and location.

Receive $20.00 off your first year of SATFISH by entering the code: GOODKARMA at checkout.

Once you have created your account, you can download the SatFish app on iOS or Android to plan your offshore fishing trips. During the 30-day free trial period, you can access all of the app’s features, including high-definition satellite imagery, real-time sea surface temperature data, and advanced planning tools. If you decide to continue using the app after the free trial period ends, you will be charged the regular subscription fee.


If you’re looking to get in on some great fishing this April, you’ll need to be in the right place at the right time – before the news hits the internet. The trick is to be one step ahead of everyone else, and these insider tips can help. In addition, you now have a formula for predicting tailing conditions and 2 Florida Keys fishing spots that you can use to help get you dialed in on epic fishing, just like the pros. Remember, it is all about timing. There is no secret why some fishing teams and fishing charters are always the first to produce epic catches; now you have a formula with the actual secret to why some fishermen catch more than others consistently.