Whether the fish you’re trying to keep healthy are in the bait tank or in the livewell, there are several tricks that you can use to keep them alive — or at least tasty — during the summer, and they all boil down to one thing: oxygen levels. Once you understand how to control and manipulate oxygen levels or the fish’s intake of oxygen, keeping them alive isn’t that hard. Here are some tips:

Oxygen tanks: Higher water temperatures reduce dissolved oxygen that fish need to survive. By inducing pure oxygen into the water via a regulated flow of oxygen dispersed through an air stone, higher dissolved-oxygen levels can be maintained even in higher water temperatures.

A portable oxygen system can be obtained online through retail tackle warehouses or bought at some high-end bait and tackle stores. Oxygen refills can be obtained at welding supply houses, medical supply stores or these same shops.

Fizzing: Aimed at fish in the livewell, fizzing entails ventilating the air bladder of a fish caught from deep water so it swims upright in the livewell rather than on its side where only one gill can reach the water. Watch a few Youtube videos and carry a No. 4 hollow needle (available at horse or veterinary supplies are sold), and you’ll soon be a pro at it.

Weighting: A layman’s version of fizzing, some anglers prefer to make fin weights by wiring an alligator clip to a 2- to 4-ounce sinker. The weight is clipped to the fish’s pectoral fin, making it ride upright in the livewell.

Add ice: Adding ice cools the bait tank or livewell water and helps it hold more dissolved oxygen. When adding ice, don’t use store-bought ice or any other ice made from chlorinated water; that will only remove oxygen, not add it. Lake or well water frozen beforehand in milk jugs or liter bottles is a good way to make your own chlorine-free ice.

Livewell extensions: Water retrieved from below the surface can be 10 or more degrees cooler than surface water, which is where the livewell or bait tank pump intakes are. To retrieve cooler water from below, use an extension hose either on your livewell intake or a separate pump to siphon water from the depths.

Straight to the cooler: If you’re not planning to release fish, put fish destined for the table directly on ice, and use lots of it. Fish will chill faster and not marinate all day in a warm soup, making the meat much tastier on the table.