How To Keep Fish Healthy In Warm Water Temps

How To Keep Fish Healthy In Warm Water Temps

This time of year can be very stressful for fish. High water temps, reduced oxygen in the water, and pressure from fishing can have a negative effect on the resource and fish mortality. As we are experiencing near record low flows and ever increasing water temps this year, it’s more important than ever that we follow some basic guidelines to keep our fish healthy.  

Water Temps 

Water temp graphic courtesy fo Colorado Trout Unlimited

One of the biggest and most important things to keep in mind this time of year is water temps. Below 65 degrees, trout are happy and healthy and you’ve got nothing to worry about. From 65-68 degrees you should exercise caution. Fish early in the day when water temps are at their lowest and follow the recommendations below to help minimize your impact on the fishery. Above 68 degrees, it’s time to think about something else to do. 

Currently the Yellowstone River is hitting 68-69 degrees in the afternoon on a regular basis. Plan to fish early when water temps are at their lowest. You can find a real time update on water temps on the USGS website here. This gauge is in town, but there are a couple more along the river that you can check based on where you’re going. 

When water temps rise above 72 degrees for three consecutive days, Montana FWP will step in with a Hoot Owl Restriction. This means no fishing from 2pm to midnight each day. We currently have several Hoot Owl Restrictions in place around the area (and a couple outright fishing closures) - you can find the latest news here on the Montana FWP website

Barbless Hooks 

This is a very easy solution to an ongoing problem. Fishing barbless hooks makes it easier to remove your fly from the fish. This reduces your handling time and gets the fish back in the water that much faster. Barbs can often get hung up on a trout’s mouth and cause additional damage as the hook is removed. Barbless hooks don’t have this problem. 

More and more commercially tied flies are coming barbless, and we stock a number of options. If your flies still have the barbs on them, they’re easy enough to pinch down. Simply use the smooth portion on the jaws of your forceps and gently crimp the barb to flat.

Remember, barbless hooks are required in places like Yellowstone National Park and some private water in the area. While they aren’t required on most rivers in Montana, pinching your barbs is a good habit to get into.

And, we like to say, barbless hooks are easy on the fish and easy on the fishermen, if by chance an errant cast should put a fly in your arm, or elsewhere.

Landing Fish Efficiently

Another key factor in keeping fish healthy during warm water temps is landing them quickly. A good rule of thumb is to use a heavier tippet than you normally would. This will let you fight the fish quickly and get them to hand much faster than if you are worried about breaking a delicate 4x or 5x. The heavier tippet also balances well with larger flies typically fished later in the summer like Chubbies and Hoppers. 

This time of year, it’s not about “the fight”. Don’t try to play the fish, don’t try to “let them run”, don’t try to see how sporting they are. Just get them to the net as quickly as you can without breaking them off. Once that fish eats your fly it’s like a countdown starts. Get them in, unhooked and released quickly before their time runs out. 

A good landing net is important for proper fish handling. It’s easier than trying to scoop the fish up with your hands, and can make the landing process faster when things are hot. Get a net with rubber netting, this is much easier on the fish. Fabric nets can dig into the fish and remove parts of their protective slime layer as well.


Keep Them Wet 

This time of year it’s extremely important to keep fish in the water once you land them. Using your net to contain them, keep the fish in the water while you remove the hook. ALWAYS take your gloves off before handling fish, and dip your hands in the water to wet them before picking up or handing them. Never put fish on a grassy bank or bankside rocks. 

If you do want to get a picture of your fish, get it quickly and while the fish is in the water. High summer is not the time for the classic grip and grin shots. Get creative with camera angles and framing if you really want a photo, or just skip the picture and get the fish back in the water ASAP. If you do have to lift the fish from the water, make sure everything is set before taking the fish out, and hold it no more than a foot above the water. However, this time of year with water and air temps being as high as they are, just keep the fish in the water. 

Another note on pictures - if you do take some (and we aren’t saying you shouldn’t, just be smart about it), don’t feel like you have to get a dozen different angles, compositions, and lighting options. Take a quick photo and get the fish back. Enjoy the moment instead of trying to get that perfect photo for the ‘gram.  

Never Pose A Fish Over The Boat 

Why is posing a fish for a photo over a boat a bad idea? Several reasons. First, it keeps the fish out of the water for a significant amount of time. Every second counts, and it often takes way too long to unhook the fish, position everyone, get a couple of shots and then try to get the fish back in the water. Generally, a fish is out of the water for this entire process. 

Secondly, have you ever held a trout? Even exhausted from trying to survive in high water temps they have a lot of fight in them. Everyone who has ever tried to hold one has dropped it. If you drop a fish over water, it falls in the river and nothing bad happens. Drop one in a drift boat or raft and it’s bonking into coolers, the hard floor or raft frame, sliding under things, getting coated in sand and dirt… 

Holding a fish over a boat is just a bad deal. Don’t do it.

While we typically don’t see these kinds of water temps and flows until late August, this year it’s come early. There’s nothing we can do about it except be responsible, obey regulations when closures do happen, and be smart. Conservation comes down to a personal choice. The health and future of the fishery is truly in your hands, every time you step in the water.