“An aquarium suffering from a spike in temperature has several visible signs,” Matt Hayes of Fish Shop Matt explains. They include: Cloudy or murky water, which happens due to increased bacterial activity (this is also a sign that the tank is cycling or the biological filter was disturbed). Fish gravitating toward aeration devices or the water’s surface and gasping,You aren’t the only one who struggles to keep cool during the summer—your fish do too. If your home gets hot—whether your air conditioning is overwhelmed or you don’t have it—so does the water in your aquarium. Unfortunately, the higher water temperatures can lead to many issues, such as reduced oxygen levels and stressed fish. In addition to these emergency situations, there are some species of fish that prefer cooler temperatures, and some tanks that can overheat if they include a lot of equipment. Fortunately, by watching out for a few clear signs and acting when you spot a problem, you can cool things down for your fish. Whether you’re new to aquariums or just trying to plan ahead, this guide covers what to look for and the best ways to keep your aquarium safe and stable.